cGVHD Model Research Articles

Mineralocorticoid receptor expression and the effects of the mineralocorticoid receptor antagonist spironolactone in a murine model of graft-versus-host disease

PurposeThe topical administration of spironolactone, a mineralocorticoid receptor antagonist (MRA) improves dry eye symptoms in patients with ocular graft-versus-host disease (GVHD); however, the detailed mechanism remains unclear. This study aimed to investigate the effects of spironolactone eyedrops on the ocular surface using a chronic GVHD (cGVHD) mouse model and to determine the expression of the mineralocorticoid receptor (MR). MethodsA cGVHD mouse model was established by allogeneic bone marrow transplantation (BMT) from B10.D2 mice to BALB/c mice. Subsequently, cGVHD mice were treated with either 0.005 % spironolactone or vehicle eyedrops. The eyelids, cornea and conjunctiva of the recipients were analyzed at 4-week intervals post-BMT in both groups. ResultsSigns of ocular GVHD, such as corneal epithelial damage, depletion of meibomian glands, and inflammatory cell infiltration onto the ocular surface, were significantly decreased in cGVHD mice treated with spironolactone eyedrops. The expression of the MR NR3C2 in the corneal and conjunctival epithelia was significantly increased in cGVHD mice. HSP47+NR3C2+ MR-expressing fibroblasts, CD45+NR3C2+ MR-expressing leukocytes, and CD4+NR3C2+ MR-expressing T cells infiltrated the ocular surface tissue of cGVHD mice significantly more than that of syngeneic controls. ConclusionsMR expression is increased in epithelial cells, fibroblasts, and T cells in a murine cGVHD model, whereas MRA and spironolactone eyedrops could attenuate the severity of ocular GVHD. These findings suggest that MR signaling partially contributes to the development of ocular GVHD in this mouse model.

A Novel Murine Model for Lupus-Like Ocular Chronic Graft-Versus-Host Disease.

Lupus-like chronic graft-versus-host disease (cGVHD) has been previously described, but the ocular findings have not been elucidated. Recipient mice in a lupus-like cGVHD model manifested notable and persistent ocular surface phenotypes. Herein, we further explored immunopathogenic mechanisms underlying these ocular phenotypes. A previously described lupus-like cGVHD model was established by intraperitoneal injection of splenocytes from bm12 mice into C57BL/6J mice. Systemic findings were evaluated for the presence of splenomegaly, proteinuria, and autoantibodies. Comprehensive evaluations were conducted on ocular manifestations and immunopathological features in this model. The lupus-like cGVHD model was successfully constructed 2 weeks post-transplantation. The recipient mice developed lupus-like phenotypes, including splenomegaly, proteinuria, and increased autoantibodies, and their ocular presentations included corneal epithelial defects and decreased tear secretion. Histological analysis revealed a reduction in corneal nerve fiber density and corneal endothelial cells, along with conjunctival fibrosis and loss of goblet cells. Moreover, cGVHD induced progressive aggravation of immune cell infiltration and fibrosis in the lacrimal glands. RNA-Sequencing (RNA-seq) results of the lacrimal glands demonstrated that the differentially expressed genes (DEGs) between the control and cGVHD groups were associated with GVHD pathways. Immune infiltration analysis using RNA-seq and flow cytometry confirmed that CD8+ T lymphocytes predominantly constituted the inflammatory infiltrating cells within the lacrimal glands. This lupus-like cGVHD model (bm12→C57BL/6J) exhibited persistent ocular surface manifestations, characterized by immune infiltration of CD8+ T lymphocytes in the lacrimal glands. Thus, this ocular cGVHD model may be used to explore the underlying mechanisms and discover novel therapeutic interventions.

Clinical study of the cytokine panel in the diagnosis of ocular chronic graft-versus-host disease

Objective: To investigate the association between cytokines and ocular chronic graft-versus-host disease (cGVHD) and identify specific biomarkers for ocular cGVHD to enhance clinical diagnosis, treatment, and evaluation. Methods: A mouse model of cGVHD was established to explore the correlation between cGVHD and serum cytokines. Based on the findings from the animal experiments and literature review, a panel of 16 cytokine combinations was identified. Enzyme-linked immunosorbent assay (ELISA) was used to compare the cytokine concentrations in the serum and tear samples from patients who underwent allogeneic hematopoietic stem cell transplantation from June 2017 to March 2022 at the Medical Center of Hematology, Xinqiao Hospital, Army Medical University. Results: ① Compared with the control group, mice with cGVHD exhibited elevated serum IL-1β, IL-6, IL-8, IL-17, IFN-γ, CX3CL1, CXCL11, CXCL13, CCL11, and CCL19 concentrations (all P<0.05). ② Analysis of the cytokine profiles of the serum and tear samples revealed that compared with patients without ocular cGVHD, those with ocular cGVHD exhibited increased serum IL-8 [P=0.032, area under the curve (AUC) =0.678]; decreased serum IL-10 (P=0.030, AUC=0.701) ; elevated IL-8, IFN-γ, CXCL9, and CCL17 in tear samples; and lower IL-10 and CCL19 in tear samples (all P<0.05, all AUC>0.7). Moreover, cytokines in tear samples showed correlations with ocular surface parameters related to ocular cGVHD. Conclusions: Tear fluid demonstrates greater specificity and sensitivity as a biomarker for diagnosing ocular cGVHD than serum biomarkers. Among the identified cytokines in tear samples, IL-8, IL-10, IFN-γ, CXCL9, CCL17, and CCL19 serve as diagnostic biomarkers for ocular cGVHD post-transplantation, offering practical reference value for diagnosis.

A Novel Dual Kinase Inhibitor for the Treatment of Chronic Graft Vs. Host Disease

Chronic Graft vs. Host Disease (cGvHD) remains a major debilitating and potentially fatal sequelae of allogeneic hematopoietic cell transplantation. Corticosteroids remain the initial therapy of clinically significant cGvHD. Since 2017 three targeted therapies have been approved for steroid refractory cGVHD, ruxolitinib, a JAK 1/2 inhibitor, is approved post one or two previous therapies. Ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor, and belumosudil, a ROCK2 inhibitor, are both approved after two previous lines of therapy. We tested RR- RR-1752 a single digit nM dual ROCK/AURK inhibitor in a mouse model of severe cGVHD. BALB/c recipient mice were preconditioned with 7.5 Gy TBI, 8 hours later they received 10 7 T-cell depleted (TCD) C57BL/6 bone marrow cells alone (Group A, n=7) or 10 7 TCD C57Bl bone marrow cells plus 10 6 splenocytes (Groups B, n=8 and C, n=8). Beginning day 7 post cell infusion animals received either oral vehicle control (groups A and B) or vehicle with 1.0 mg/kg RR-1752 (Group C) daily. Body weight, alopecia score and eye score were monitored 3×/week through day 56 or until termination. All animals in groups B and C developed signs and symptoms of chronic graft vs. host disease. Animals in group A exhibited 20% weight loss through seven days post irradiation and cell infusion but began to recover to baseline and recovered weight to 90% of baseline. Animal weights in groups B and C dropped to less than 80% at day seven post irradiation, but only recovered to 80.38% +/- 10.18 (Group B) and 87.11% +/- 7.90 (Group C) on day 14 and then declined to 74.10% +/- 4.19 in Group B and 80.23% +/- 7.35 in Group C by day 28 (Figure 1). Animals in Group A had no significant change in eye score or alopecia. In contrast all animals in groups B and C showed signs of cGvHD. Eye showed moderate effects in Group B and mild changes in group C, while alopecia scores were moderate in both groups B and C. All animals in group A survived through day 56, median survival in group B was 16.5 days, as compared to 38 days in group C (Figure 2). In a separate study in normal mice, RR-1752 given at 1.0 mg/kg/day for 2 weeks showed no negative effects on hemoglobin, hematocrit, platelets, total WBC, or neutrophils, and only a mild decrease in lymphocytes. Using a model for cGVHD, exhibiting weight loss, alopecia, and ocular changes, we demonstrated that RR-1752 1.0 mg/kg/day slows mouse body weight loss, increases survival and shows trends to ameliorate ocular toxicity. The dose tested did not ameliorate the alopecia in the cGVHD mice. Further studies are ongoing to assess higher dose levels and dose schedule effects in the severe cGVHD mouse model. Additional studies to compare effects on cGVHD to ruxolitinib and belumosudil and in combination with those standard of care therapies need to be conducted.

Mitochondrial Pyruvate Carrier Inhibition Mitigates Murine Chronic Graft Versus Host Disease By Attenuating the Germinal Center Reaction

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potent therapy for many hematopoietic diseases and malignancies. However, the long-term efficacy of allo-HSCT is limited by the development of chronic graft versus host disease (cGVHD). During cGVHD, interactions between donor-derived T follicular helper cells (TFH) and germinal center B cells (GCB) result in the production of alloreactive class-switched affinity-matured antibodies that attack host tissues, causing multi-organ damage and tissue fibrosis. Novel treatment approaches are warranted to treat cGVHD since it is often refractory to current broad immune suppressive drugs. In this study we sought to delineate the metabolic dependencies of germinal center (GC) immune cells to discover new strategies to treat active murine cGVHD. We utilized a multi-organ mouse model of cGVHD that includes bronchiolitis obliterans (BO), a severe cGVHD manifestation seen in the clinic. Toward that end, B10.BR (H2 k) recipients received myeloablative conditioning with cyclophosphamide and total body irradiation before receiving MHC mismatched C57BL/6 (H2 b) donor T cell depleted bone marrow with (cGVHD) or without (BM only control) a low dose of splenic T cells. First, we sought to assess the metabolic dependencies of TFH during cGVHD progression through Seahorse metabolic flux assays. TFH sorted early (D28) from cGVHD mice were highly glycolytic with an increased extracellular acidification rate (ECAR) and less reliant on oxidative phosphorylation (OXPHOS) as reflected by a decreased oxygen consumption rate (OCR). However, TFH sorted later (D49) from cGVHD mice demonstrated a dramatic shift in their metabolic profile to a decreased ECAR and an increased OCR indicating a transition from glycolysis towards OXPHOS as disease progresses. To understand which substrates are driving increased OXPHOS and to identify promising metabolic targets, we performed unbiased metabolomics of sort purified TFH from BM only and cGVHD mice on D49 post-transplantation (Fig A). Among the top fifty differential metabolites, cGVHD TFH had a decreased abundance of anaplerotic amino acids (serine, glutamine) and an increased abundance of multiple breakdown products of anaplerotic amino acids (tryptophan, leucine), indicative of increased replenishment of tricarboxylic acid (TCA) cycle intermediates. Notably these metabolomics data showed a decreased abundance of glutamine which is consistent with an increase in glutaminolysis, validating our prior findings that TFH cells that cause cGVHD/BO depend on glutaminolysis ( Johnson MO, Cell 2018). Additionally, there was an increased abundance of pyruvate, which can be transported into mitochondria to fuel the TCA cycle through the mitochondrial pyruvate carrier (MPC). Based on these findings we chose to target the MPC since it has a central role in tying pyruvate to the TCA cycle and OXPHOS. We assessed the effect of an MPC inhibitor (7ACC1) on the GC reaction utilizing an ex vivo co-culture assay of TFH and B cells. 7ACC1 added to this co-culture system resulted in a significant reduction in the production of class-switched immunoglobulin compared to vehicle treatment. To assess the in vivo efficacy, we administered 7ACC1 daily through intraperitoneal injections after establishment of cGVHD (Days 28-49) in the cGVHD/BO mouse model. 7ACC1 treatment resulted in a significant reduction of the GC reaction with significantly decreased TFH and GCB frequencies. Additionally, there was a significant improvement in cGVHD disease severity as evidenced by assessing pulmonary function tests in anesthetized, intubated and mechanically ventilated mice using plethysmography. In contrast to the high resistance and low compliance seen in cGVHD/BO mice, 7ACC1 treated recipients had significantly improved lung function, comparable to the BM only controls (Fig B). In summary, inhibiting MPC mediated transport of pyruvate represents a novel approach to stifling the metabolic demands of TFH as their energy dependency shifts from glycolysis towards OXPHOS during the course of cGVHD/BO disease progression.

Inhibition of Bromodomain and Extraterminal Domain (BET) Proteins Alleviates Chronic Graft- Versus-Host-Disease Via Modulating the CXCR5/CXCL13 Axis

Introduction: Chronic graft-versus-host disease (cGVHD) is a severe complication of allogeneic hematopoietic cell transplant (allo-HCT) often leading to transplant-mediated mortality. Studies have shown that T follicular helper cells (Tfh) upregulate CXCR5 and migrate into the lymphoid organ follicles in response to CXCL13 promoting germinal center (GC) B cell proliferation and differentiation of plasma cells resulting in pathogenic antibody production and profibrotic pathways associated with cGVHD. In contrast, T follicular regulatory cells (Tfr) modulate the magnitude of the GC response; thus, the balance of Tfr/Tfh could be crucial to mitigating cGVHD.Bromodomain and extra-terminal domain (BET) proteins are epigenetic readers influencing transcription of a multitude of inflammatory genes and our lab has previously reported pharmacological inhibition of BET, through OPN-51107, improves survivability and limits disease progression in murine models of acute GVHD that led to opening the first-in-human clinical trial of OPN-51107 in steroid refractory acute GVHD. We demonstrated BET proteins to be important in modulating acute GVHD pathogenesis, however, mechanisms of BET regulation within cGVHD are largely unknown. Here, using OPN-51107 we aim to further investigate mechanisms of cGVHD pathogenesis and identify successful BET inhibition-based therapeutic approaches. Methods: We used a Bronchiolitis Obliterans model (B6-&amp;gt;B10.br) of cGVHD. Mice were administered 120mg/kg cyclophosphamide (D-3 and D-2) and 8Gy irradiation (D-1) as a conditioning regimen followed by B6 T-cell depleted bone marrow cells with and without CD45.1 B6 splenocytes. Mice that did not receive allogeneic splenocytes served as controls and did not develop GVHD. Recipients of allogeneic splenocytes were treated with a BET inhibitor - OPN-51107 at 10mg/kg 3x/weekly, or vehicle, from D28-54(+ 4) via oral gavage. Resting lung elastance and resistance was measured using the Flexivent system. At the time of lung function analysis, lung and liver tissue was harvested and stained via Hesson's Trichrome to identify and quantify collagen deposition. We performed immunofluorescence to quantify alveolar alloantibody deposition. Spleen and lung cells were stimulated with PMA/I and analyzed via spectral flow cytometry. An inflammatory murine cytokine array (#ARY006, R&amp;D Systems) was used to analyze circulating plasma cytokine levels. Results: BET inhibition via OPN-51107 treatment decreased lung resistance (vehicle vs OPN-51107 =1.16Rrs vs 0.83Rrs p&amp;lt;0.05) and elastance (vehicle vs. OPN-51107=62Ers vs. 45Ers p&amp;lt;0.05). OPN-51107 treatment also significantly reduced alveolar antibody (Ig) deposition per area compared to vehicle (vehicle vs. OPN-51107= 4.91% vs. 3.3% p=0.01) and collagen deposition (vehicle vs. OPN-51107=19.0% vs. 12.9% p&amp;lt;0.05) and liver (vehicle vs. OPN-51107=19.3% vs. 2.35% p&amp;lt;0.0001). Congruently, BET inhibition decreased B220-CD19- CD138+mature plasma cells (vehicle vs. OPN-51107=15% vs 9.1% p&amp;lt;0.05) in the lung. Serum cytokine array analysis revealed a significant decrease in circulating CXCL13, relevant to Tfh migration as well as a decrease in other proinflammatory cytokines - CXCL9, MCP-1, IL3, RANTES and G-CSF important for macrophage activation and pathogenicity in OPN-51107 compared to vehicle treated mice. BET inhibition reduced splenic Tfh while increasing Tfr, thereby increasing Tfr:Tfh ratio (vehicle vs. OPN-51107= 5% vs. 9% p&amp;lt;0.05). Furthermore, total splenic CD19+ B-cells (vehicle vs. OPN51107= 70% vs. 33% p&amp;lt;0.001) as well as CXCR5 expression on B-cells were decreased in OPN-51107 treated mice (MFI vehicle vs. OPN-51107= 4744 vs. 571.5 p&amp;lt;0.0001). Conclusion: OPN-51107 improved lung function which correlated with significantly decreased lung fibrosis and antibody deposition in a BO model of cGVHD. BET inhibition reduces cGVHD immune pathology through decreased inflammatory cytokine production, promotion of GC Tfr cell population and modulates B-cell proliferation and/or trafficking. Significance: Using OPN-51107 in a BO model of cGVHD we demonstrate that BET inhibition is a feasible therapeutic strategy to reduce disease severity and improve lung function.

Combinatorial inhibition of Tec kinases BTK and ITK is beneficial in ameliorating murine sclerodermatous chronic graft versus host disease.

Graft-versus-host disease (GVHD) is the major factor limiting the widespread use of potentially curative allogeneic hematopoietic stem cell transplant (allo-HSCT). Chronic GVHD is characterized by the activation of alloreactive donor immune cells, especially B- and T-cells, leading to tissue damage and pathogenic fibrosis. In this study, we used highly specific next-generation inhibitors of ITK (PCYC-274), BTK (PCYC-804), and ibrutinib-like BTK/ITK inhibitors (PCYC-914 and PCYC-401) in the B10.D2 → BALB/C model of murine sclerodermatous cGVHD. From the third week onward, allogeneic recipients in each group of respective Tec kinase inhibitors were treated three times weekly with inhibitors at doses of 10 and 30 mg/kg or with saline control via oral gavage. Overall, we found that selective BTK inhibition was less effective than combined ITK/BTK or ITK inhibition in lengthening survival and reducing symptoms of cGVHD. ITK inhibition was most efficacious, with PCYC-274 and PCYC-401 demonstrating a nearly 50 percent reduction in GVHD scoring even at the 10 mg/kg dose, while 30 mg/kg of these compounds almost completely ameliorated GVHD symptomology. BTK/ITK and ITK-treated mice showed significant reductions in overall pathology. Significant reductions in dermal thickness and fibrosis were shown for all treatment groups. There was evidence of mixed Th1 and Th2 cytokine profiles in the skin of mice with dermal cGVHD, as both IFN-gamma and IL-4 were upregulated in the allogeneic control group, while kinase inhibition significantly reduced levels of these cytokines. Using an in vitro model of T-cell polarization, Th1 cell production of TNF-alpha and IFN-gamma were partially blocked by ITK. Th2 cell production of IL-4 was almost completely blocked synergistically by ITK and BTK inhibition. BTK-specific inhibition was unable to block either Th1 or Th2 cytokine production. Taken together, these results confirm previous reports that ITK-focused inhibition inhibits Th1 and Th2 cells. Additionally, the compound's effects on T-cell proliferation were tested by CFSE assay. Pure ITK inhibition was most effective at blocking T-cell proliferation, with no proliferation in PCYC-274-treated cells even at 0.1uM. PCYC-401 and PCYC-914 showed some inhibition at lower doses, with complete inhibition evident at 10uM. PCYC-804 was only partially able to block proliferation even at 10uM. In conclusion, we observed substantial benefit for differential inhibition of Tec kinases in GVHD, with ITK being most efficacious and Th1 cells being more resistant to inhibition, matching the previously reported findings of a Th2 to Th1 selective pressure in cells treated with ibrutinib. Our data warrants the further development of ITK and ITK/BTK inhibitors with specific inhibitory ratios to improve the treatment of GVHD and other T-cell mediated diseases.

Targeting Bcl-6 prevents sclerodermatous chronic graft-versus-host disease by abrogating T follicular helper differentiation in mice.

Chronic graft-versus-host disease (cGVHD) is the most common cause of non-relapse mortality (NRM) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). CD4+ follicular helper T (Tfh) cells, specialized providers of T cell help to B cells, play a vital role in GVHD pathogenesis. B-cell lymphoma-6 (Bcl-6) transcription factor has been shown to be required for Tfh-mediated germinal center reactions. In this study, we would like to evaluate the effect of Bcl-6 on Tfh function in sclerodermatous cGVHD and the efficacy of Bcl-6 inhibitors (Bcl-6i) for treating a minor histocompatibility complex (miHC) mismatch model of sclerodermatous cGVHD (scl-cGVHD). A minor histocompatibility haploidentical model of scl-cGVHD was established and received intraperitoneal injection of 79-6, a small-molecule inhibitor of Bcl-6. The clinical manifestations and survival times of cGVHD mice were recorded. The histological assessment was performed by hematoxylin-eosin (HE) and Masson's trichrome staining on the skin and lung tissues. Tfh cells and germinal center B cells in the spleen and peripheral blood were detected by flow cytometry. The cellular markers were immunostained in different organs. ELISA was performed to detect cytokine secretion. Bcl-6 inhibition by 79-6 improved the clinical manifestation of scl-cGVHD mice and prolonged their survival. The histopathologic damage, particular the fibrotic changes of scl-cGVHD mice was significantly relieved after 79-6 treatment. Furthermore, 79-6 treatment not only suppressed the development and function of Tfh and Tph cells in the peripheral blood, but also reduced the survival of Tfh cells in the spleen. Moreover, 79-6 decreased the frequency of GC plasmocytes accompanied by a reduction in IL-21. Our study demonstrates that Bcl-6 inhibitor could prevent murine sclerodermatous chronic graft-versus-host disease by abrogating T follicular helper differentiation and suppressing the function of GC B cells, indicating that Bcl-6 inhibition may be a potential treatment for patients with cGVHD.

Novel pre-clinical mouse models for chronic Graft-versus-Host Disease.

Despite considerable progress in allogeneic hematopoietic cell transplantation (allo-HCT) has been achieved over the past years, chronic Graft-versus-Host Disease (cGvHD) still contributes to high morbidity rates, thus remaining a major hurdle in allo-HCT patients. To understand the complex pathophysiology of cGvHD and to develop refined prophylaxis and treatment strategies, improved pre-clinical models are needed. In this study, we developed two murine cGvHD models, which display high long-term morbidity but low mortality and depict the heterogeneous clinical manifestations of cGvHD seen in patients. We established a haploidentical C57BL/6→B6D2F1 allo-HCT model that uses myeloablative radiation and G-CSF-mobilized splenocytes as stem cell source and a sub-lethally irradiated Xenograft model, which utilizes the transfer of human peripheral blood mononuclear cells (PBMCs) into NOD scid gamma (NSG)-recipients. We characterized both mouse models to exhibit diverse clinical and histopathological signs of human cGvHD as extensive tissue damage, fibrosis/sclerosis, inflammation and B cell infiltration in cGvHD target organs skin, liver, lung and colon and found a decelerated immune cell reconstitution in the late phase after HCT. Our pre-clinical models can help to gain a deeper understanding of the target structures and mechanisms of cGvHD pathology and may enable a more reliable translation of experimental findings into the human setting of allo-HCT.

LncRNA IL21-AS1 interacts with hnRNPU protein to promote IL21 overexpression and aberrant differentiation of Tfh cells in systemic lupus erythematosus.

The aberrant differentiation of T follicular helper (Tfh) cells plays an important role in the pathogenesis of systemic lupus erythematosus (SLE). However, the mechanism of regulating Tfh cells differentiation remains unclear. Long noncoding RNAs (lncRNAs) act as important regulators in the processes of innate and adaptive immune response. Whether lncRNAs are involved in regulating Tfh cell differentiation and autoimmune responses need to be further identified. The characters and functions of human IL21-AS1 and its mouse homologous lncRNA (mIl21-AS) were investigated by a series of biochemical assays and cell transfection assay. mIl21-AS1 regulating humoral immune response in vivo was explored by keyhole limpet haemocyanin (KLH) and chronic graft versus host disease (cGVHD) model. Human IL21-AS1 and its mouse homologous lncRNA (mIl21-AS) were identified and cloned. We uncovered that IL21-AS1 was highly expressed in CD4+ T cells of SLE patients and Tfh cells, which promoted differentiation of Tfh cells. Mechanistically, IL21-AS1 bound heterogeneous nuclear ribonucleoprotein U and recruited acetyltransferases CREB-binding protein to the promoter of IL21, leading to the transcriptional activation of IL21 and Tfh cells differentiation through increasing Histone H3 acetylation level on IL21 promoter. Moreover, Tfh proportion and antibodies production were significantly increased in mIl21-AS knock-in mice immunized with KLH. mIl21-AS1 overexpression also exacerbated the lupus-like phenotype in cGVHD mice model. Our results demonstrate that IL21-AS1 activates IL21 transcription via epigenetic mechanism to promote germinal centre response, adding insight into the molecular regulation of autoimmune pathogenesis and providing a novel target for SLE treatment.

Trafficking between clonally related peripheral T-helper cells and tissue-resident T-helper cells in chronic GVHD

AbstractChronic graft-versus-host disease (cGVHD) is an autoimmune-like syndrome. CXCR5-PD-1hi peripheral T-helper (Tph) cells have an important pathogenic role in autoimmune diseases, but the role of Tph cells in cGVHD remains unknown. We show that in patients with cGVHD, expansion of Tph cells among blood CD4+ T cells was associated with cGVHD severity. These cells augmented memory B-cell differentiation and production of immunoglobulin G via interleukin 21 (IL-21). Tph cell expansion was also observed in a murine model of cGVHD. This Tph cell expansion in the blood is associated with the expansion of pathogenic tissue-resident T-helper (Trh) cells that form lymphoid aggregates surrounded by collagen in graft-versus-host disease (GVHD) target tissues. Adoptive transfer experiments showed that Trh cells from GVHD target tissues give rise to Tph cells in the blood, and conversely, Tph cells from the blood give rise to Trh cells in GVHD target tissues. Tph cells in the blood and Trh cells in GVHD target tissues had highly overlapping T-cell receptor α and β repertoires. Deficiency of IL-21R, B-cell lymphoma 6 (BCL6), or T-bet in donor T cells markedly reduced the proportions of Tph cells in the blood and Trh cells in GVHD target tissues and reduced T-B interaction in the lymphoid aggregates. These results indicate that clonally related pathogenic Tph cells and Trh cells traffic between the blood and cGVHD target tissues, and that IL-21R-BCL6 signaling and T-bet are required for the development and expansion of Tph and Trh cells in the pathogenesis of cGVHD.

Pharmacological targeting EZH2 to modulate chronic graft-versus-host disease

Pharmacological targeting EZH2 to modulate chronic graft-versus-host disease

IL-39 promotes chronic graft-versus-host disease by increasing T and B Cell pathogenicity

BackgroundChronic graft-versus-host disease (cGVHD) remains a major complication during the late phase of allogeneic hematopoietic stem cell transplantation (allo-HSCT). IL-39, a newly described pro-inflammatory cytokine belonging to the IL-12 family, plays a role in lupus development. Recently, IL-39 has been identified as a pathogenic factor in acute GVHD (aGVHD). However, the role of IL-39 in the pathogenesis of cGVHD remains unclear.MethodsWe constructed a recombinant IL-39 plasmid and established scleroderma and lupus-like cGVHD models. Quantitative PCR and enzyme-linked immunosorbent assay (ELISA) were used to detect IL-39 expression in mice and patients post transplantation, respectively. Hydrodynamic gene transfer (HGT) was performed to achieve IL-39 overexpression in vivo. Multiparameter flow cytometry, western blotting, and assays in vitro were performed to investigate the effect of IL-39 on cGVHD.ResultsThe relative expression of IL-23p19 and EBi3 was significantly increased in the intestine of cGVHD mice on day 40 post allo-HSCT, and IL-39 levels were significantly elevated in the serum of patients following allo-HSCT. Overexpression of IL-39 significantly aggravated the severity of cGVHD. Increased IL-39 levels promoted T-cell activation and germinal center responses, and may exacerbate thymic damage. Consistently, blocking IL-39 markedly ameliorated immune dysregulation in the cGVHD mice. Furthermore, we found that IL-39 was produced by B cells, CD11b+ cells, and CD8+T cells after activation. Stimulation of IL-39 led to upregulation of the IL-39 receptor on CD4+T cells and further caused activation of the STAT1/STAT3 pathway, through which IL-39 may exert its pro-inflammatory effects.ConclusionOur study reveals a critical role for IL-39 in cGVHD pathogenesis and indicates that IL-39 may serve as a potential therapeutic target for cGVHD prevention.

Targeting temporal metabolic needs of T follicular helper cells to treat cGVHD utilizing a mitochondrial pyruvate carrier inhibitor

Abstract The curative potential of allogeneic hematopoietic stem cell transplantation is limited by development of chronic graft versus host disease (cGVHD) and metabolic regulation of immune cells is a promising therapeutic target. During cGVHD, interactions between T follicular helper (TFH) and germinal center B (GCB) cells result in production of alloreactive class-switched antibodies that attack host tissues, causing multi-organ damage and tissue fibrosis. We show the metabolic dependencies of TFH change throughout cGVHD progression and targeting mitochondrial pyruvate transport is an effective strategy to mitigate disease. Pyruvate, the end product of glycolysis, is transported by the mitochondrial pyruvate carrier (MPC) for use in the tricarboxylic acid cycle and oxidative phosphorylation (OXPHOS). TFH require glycolysis in order to induce a GC reaction, both in an immunization model and in an in vivo systemic cGVHD model with bronchiolitis obliterans (BO). Furthermore, Seahorse data from TFH extracted early in disease development in the BO model demonstrate increased dependency on glycolysis. But Seahorse data also indicates TFH undergo a shift away from glycolysis and toward OXPHOS as cGVHD continues. Based on the central role of MPC in tying pyruvate to multiple metabolic pathways, we examined an inhibitor of MPC (7ACC1) in reducing TFH activity. Administration of 7ACC1 resulted in inhibition of GCB production of class switched antibody in an in vitro assay. These findings were additionally supported in vivo, whereby daily treatment after establishment of cGVHD resulted in a decrease in disease severity. These data provide evidence that inhibiting mitochondrial pyruvate transport is a viable therapeutic strategy for cGVHD. This work was supported by grants from National Institutes of Health, National Institute of Allergy, and Infectious Diseases R37 AI34495, T32 AI007313; National Heart, Lung, and Blood Institute R01 HL56067, R01 HL11879, R01 HL115114 ; National Cancer Institute P01 CA065493

Augmenting oxidation of branched-chain amino acids (BCAAs) treats murine chronic Graft-Versus-Host Disease (cGVHD)

Abstract Aberrant immune responses, such as high Tfollicular helper (Tfh) and germinal center B cells (GCB) in cGVHD inducing antibody (Ab) secretion with tissue deposition and fibrosis, require distinct metabolic reprogramming to sustain pathogenesis. Leucine, isoleucine, and valine are essential BCAAs that signal via mTORC1 to support glycolysis and protein synthesis. Alternatively, BCAAs can be oxidized to metabolites that directly enter the tricarboxylic acid cycle or become substrates for gluconeogenesis and ketogenesis. Branched chain ketoacid dehydrogenase kinase (BDK) is a negative regulator of BCAA metabolism, decreasing downstream oxidation and increasing mTORC1 and glycolysis. We sought to determine whether increasing BCAA oxidation could be exploited to inhibit cGVHD. BDK is inhibitable by 3,6-Dichlorobenzo[β] thiophene-2-carboxylic acid (BT2), increasing BCAA oxidation and decreasing T effector (Teff) activation. In a multiorgan cGVHD model with bronchiolitis obliterans, mice that received BDK knockout vs wildtype donor T cells had improved survival and pulmonary function with decreased GCB frequencies (p-value 0.005) and a trend toward decreased Tfh/Tfollicular regulatory ratios. An in vitro assay measuring Tfh-mediated B cell Ab production showed that BT2 downregulates IgG class switching, which is key for cGVHD pathogenesis. BT2-treated T effectors but not T regulatory cells (Treg) exhibited increased oxidative phosphorylation (OXPHOS). Therefore, limiting BCAAs inhibits Teff switch from a highly glycolytic state to OXPHOS. In contrast, BCAAs are not required for Treg energy production or survival. These data suggest that augmenting BCAA oxidation could be a new therapeutic approach for treating cGVHD. Supported by NIH P01 AI056299

BET-bromodomain and EZH2 inhibitor–treated chronic GVHD mice have blunted germinal centers with distinct transcriptomes

AbstractDespite advances in the field, chronic graft-versus-host-disease (cGVHD) remains a leading cause of morbidity and mortality following allogenic hematopoietic stem cell transplant. Because treatment options remain limited, we tested efficacy of anticancer, chromatin-modifying enzyme inhibitors in a clinically relevant murine model of cGVHD with bronchiolitis obliterans (BO). We observed that the novel enhancer of zeste homolog 2 (EZH2) inhibitor JQ5 and the BET-bromodomain inhibitor JQ1 each improved pulmonary function; impaired the germinal center (GC) reaction, a prerequisite in cGVHD/BO pathogenesis; and JQ5 reduced EZH2-mediated H3K27me3 in donor T cells. Using conditional EZH2 knockout donor cells, we demonstrated that EZH2 is obligatory for the initiation of cGVHD/BO. In a sclerodermatous cGVHD model, JQ5 reduced the severity of cutaneous lesions. To determine how the 2 drugs could lead to the same physiological improvements while targeting unique epigenetic processes, we analyzed the transcriptomes of splenic GCB cells (GCBs) from transplanted mice treated with either drug. Multiple inflammatory and signaling pathways enriched in cGVHD/BO GCBs were reduced by each drug. GCBs from JQ5- but not JQ1-treated mice were enriched for proproliferative pathways also seen in GCBs from bone marrow-only transplanted mice, likely reflecting their underlying biology in the unperturbed state. In conjunction with in vivo data, these insights led us to conclude that epigenetic targeting of the GC is a viable clinical approach for the treatment of cGVHD, and that the EZH2 inhibitor JQ5 and the BET-bromodomain inhibitor JQ1 demonstrated clinical potential for EZH2i and BETi in patients with cGVHD/BO.

Efficacy of Vecabrutinib Treatment in a Murine Model of Sclerodermatous Graft-Versus-Host-Disease

Introduction. Chronic graft-versus-host disease (cGVHD) can manifest as a complication in patients following allogeneic hematopoietic stem cell transplant resulting in morbidity and mortality. Effective treatment strategies for cGVHD are currently lacking. Ibrutinib, an irreversible BTK inhibitor with activity against several other Tec-family kinases, has been clinically developed for cGVHD treatment due to regulation of pathogenetic B cells and T-cell subsets. Vecabrutinib is a more selective, reversible inhibitor of BTK with a distinct kinase domain interaction, which could result in differentiated safety and activity profiles compared to ibrutinib. Vecabrutinib has the capacity to overcome the C481S mutation that mediates resistance to ibrutinib. Vecabrutinib also also demonstrates activity against ITK, which is expressed in T cells. In this study, we investigated the activity and immune modulation of vecabrutinib treatment in a murine model of sclerodermatous cGVHD. Ibrutinib was utilized for comparison.Methods. A murine model of sclerodermatous cGVHD was initiated by adoptive transfer of T-cell depleted bone marrow plus whole splenocytes from B10.D2 donors into BALB/c recipients that were previously subjected to sub-lethal irradiation. Total bone marrow and irradiation only groups were included as controls. Mice with established cGVHD characterized by weight loss and skin irritation symptoms were treated with vecabrutinib once daily at 50mg/kg by oral gavage or ibrutinib at 30mg/kg in drinking water 5 days per week for approximately 3 weeks beginning on day 27 post-adoptive transfer and ending on day 45 (n=10 mice per group). Body weight and clinical symptoms (appearance, activity, skin symptoms, diarrhea, conjunctivitis) were measured throughout the study. Immunophenotyping for B cells and T cells was performed on spleens collected from euthanized mice by flow cytometry at two timepoints (day 40 during treatment and on day 76 post-treatment). Levels of circulating immunoglobulins were measured by multiplex cytokine assay at both timepoints.Results. Clinical symptoms, including appearance, activity, skin irritation, redness, alopecia and diarrhea were significantly reduced in vecabrutinib- and ibrutinib-treated groups. Furthermore, there was a trend toward a more favorable clinical score overall for the vecabrutinib-treated group, however no statistical difference was observed compared to ibrutinib possibly due to small sample size. Weight loss was slightly elevated during vecabrutinib and ibrutinib treatment compared to vehicle (trend), however mice recovered body weight post-treatment and continued to maintain benefit. On day 40 (during treatment) and day 76 (post-treatment) groups of mice were euthanized for immunophenotyping analysis utilizing a 22-color flow cytometry panel. During treatment, both vecabrutinib and ibrutinib-treated mice retained total B cell numbers but exhibited reduced B-cell activation, proliferation, and number of B220+ CD138+ plasma cells. In addition, B cells secreted less IL-10, and IL-4/5. Expression of antigen-presentation molecules CD80 and CD86 on B cells were unchanged. Total CD3+ T cells, activated and proliferating CD4+ and CD8+ T cells, and cytotoxic granzyme-B+ CD8+ T cells were reduced in treated mice. Interestingly, CD4+ CD25+ FoxP3+ Treg number, expression of PD-1 on Tregs and CD4+ CXCR5+ PD-1+ T follicular helper cells were also reduced in both treatment groups. In addition, there were globally reduced numbers of cytokine-secreting CD4+ cells but no differences in Th1/Th2 or Th17/Treg ratios were observed. Post-treatment, proliferation and cytokine secretion of B cells and T cells were still lowered but less impaired than during treatment. Tregs and PD-1 expression were still reduced post-treatment. Finally, circulating levels of IgA were reduced during and post treatment in vecabrutinib-treated mice compared to vehicle, while IgG1, IgG2b were reduced in both treated groups. No changes in IgM levels were observed in either treatment group. In conclusion, vecabrutinib treatment demonstrated efficacy and beneficially regulated B cell and T cell immune subsets in a preclinical murine model of sclerodermatous cGVHD. Studies to further evaluate differences between vecabrutinib and ibrutinib treatment are ongoing. [Display omitted] DisclosuresFox: Sunesis Pharmaceuticals: Current Employment. Taverna: Sunesis Pharmaceuticals: Current Employment. Pinilla Ibarz: Sellas: Other: ), patents/royalties/other intellectual property; MEI, Sunesis: Research Funding; AbbVie, Janssen, AstraZeneca, Takeda: Speakers Bureau; AbbVie, Janssen, AstraZeneca, Novartis, TG Therapeutics, Takeda: Consultancy, Other: Advisory.

Allosteric Inhibition of MALT1 Is Efficacious in a Model of Chronic Graft-Versus-Host Disease and Modulates Immunometabolic Activation

IntroductionGraft-versus-host disease (GVHD) is a severe complication of allogeneic hematopoietic cell transplantation. In its chronic form, GVHD causes prolonged post-transplant morbidity and significant mortality. There is a paucity of approved therapies and the current standard of care results in incomplete responses that leave significant unmet need for novel agents. Mucosa-associated lymphoid tissue lymphoma translocation protein-1 (MALT1) is a bi-functional protein that acts as a signal-propagation scaffold and protease for selective innate and adaptive immune cell receptor signaling. The established link between MALT1 and receptor-mediated activation of multiple immune cell types involved in cGVHD argues for it as a therapeutic target for cGVHD. Furthermore, we have identified MALT1 signaling to be important in linking receptor-initiated signaling to changes in cellular metabolism necessary for immune cell effector function and propose that immunometabolic profiling of immune cells from cGVHD patients may provide novel biomarkers of both disease pathophysiology and associated MALT1 activity.Methods, Results, ConclusionTo assess MALT1 as a novel drug target in cGVHD, we first characterized the effectiveness of allosteric inhibition on protease, scaffolding, and metabolic activity in primary human T cells. MALT1 inhibition of T-cell receptor (TCR) activated CD4 + T cells reduced protease activity by >90% and scaffolding activity by ∼50%, downstream of TCR activation. Consistent with disruption of the TCR signaling cascade, MALT1 inhibition reduced T H1 and T H17 cytokines, and the T FH cytokine IL-21 in a concentration dependent manner. B-cell receptor (BCR) driven proliferation of human B cells and C-type-lectin receptor and immune complex driven cytokine production from human macrophages were also inhibited.We next tested MALT1 inhibition in a sclerodermatous rodent model of cGVHD (scGVHD). Allogeneic bone marrow and splenocytes from LP/J donor mice were transferred to irradiated C57BL/6 recipient mice. Starting on day 21 after transfer, animals were dosed orally once daily with a MALT1 inhibitor, or twice daily with the JAK1/2 inhibitor ruxolitinib as a comparator. All animals were monitored daily for weight change, survival and GVHD score. On a modified scGVHD scoring scale, animals treated with a MALT1 inhibitor had significantly more progression-free survival throughout the study than vehicle or ruxolitinib-treated animals. No differential effect was observed on body weight and overall survival. MALT1 inhibitor treatment, but not ruxolitinib, reduced frequencies of splenic T FH cells and germinal center B cells compared with vehicle-treated mice. Importantly, MALT1 inhibition had no effect on the frequency or numbers of splenic regulatory T cells. Additionally, a delayed-type hypersensitivity (DTH) response was abrogated with MALT1 inhibition, showing that T-cell-driven responses in the skin, an important target tissue in cGVHD, can be abrogated with MALT1 blockade.Given recent studies implicating MALT1 activity as a link between immunoreceptor signaling and activation-dependent metabolic activity in T cells, we performed non-targeted metabolomics on plasma and spleens from scGVHD animals. Clustering of splenic metabolite intensities across treatment groups revealed a subset of metabolites responsive to MALT1 inhibition. This motivated us to explore the metabolic activity of cells from GVHD patients. By developing a method to infer metabolic pathway activity from transcriptional profiles of whole blood, we were able to utilize publicly available RNA-seq data. Using a data set containing 8 healthy controls and longitudinal samples from 25 GVHD patients, this approach segregated GVHD patients into four subsets, with the two largest subsets showing oppositional activity in most major metabolic pathways. Collectively, these data reveal a breadth of MALT1 activity across diverse cell types implicated in the initiation and progression of cGVHD and support development of small-molecule inhibitors of MALT1. These data also define novel heterogeneity among GHVD patients based on immunometabolic activity and motivate development of metabolic biomarkers of MALT1 activity for clinical use. [Display omitted] DisclosuresDispirito: Rheos Medicines: Current Employment. Badur: Rheos Medicines: Current Employment. Biswas: Rheos Medicines: Current Employment. Camacho: Rheos Medicines: Current Employment. Chalishazar: Rheos Medicines: Current Employment. DeChristopher: Rheos Medicines: Current Employment. Sellers: Rheos Medicines: Current Employment. Steadman: Rheos Medicines: Current Employment. Soh: Rheos Medicines: Current Employment. Monroe: Rheos Medicines: Consultancy. Long: Rheos Medicines: Current Employment.

Eyelid blood vessel and meibomian gland changes in a sclerodermatous chronic GVHD mouse model

PurposeTo investigate pathological changes in blood vessels and meibomian glands (MGs) in the eyelids of sclerodermatous chronic graft-versus-host disease (cGVHD) model mice. MethodsWe used an established major histocompatibility complex compatible, multiple minor histocompatibility antigen-mismatched sclerodermatous cGVHD mouse model. Blood vessels and MGs of eyelids from allogeneic bone marrow transplantation (allo-BMT) recipient mice and syngeneic bone marrow transplantation (syn-BMT) recipient mice were assessed by histopathology, immunohistochemistry and transmission electron microscopy. Peripheral blood samples from the recipients were examined by flow cytometry. ResultsAllo-BMT samples showed dilating, tortuous and branching vessels and shrunk MGs in the eyelids; showed significantly higher expression of VEGFR2 (p = 0.029), CD133 (p = 0.016), GFP (p = 0.006), and α-SMA (p = 0.029) in the peripheral MG area; showed endothelial damage and activation, fibrotic change, and immune cell infiltration into MGs compared with syn-BMT samples. Fewer Ki-67+ cells were observed in allo- and syn-BMT samples than in wild-type samples (p = 0.030). Ultrastructural changes including endothelial injury and activation, fibroblast activation, granulocyte degranulation, immune cell infiltration into MGs, and necrosis, apoptosis of MG basal cells were found in allo-BMT samples compared with syn-BMT samples. ConclusionA series of our studies indicated that cGVHD can cause eyelid vessel and MGs changes, including endothelial injury and activation, neovascularization, early fibrotic changes, immune cell infiltration, MG basal cell necrosis and apoptosis, and resultant MG atrophy.

Observation of Chronic Graft-Versus-Host Disease Mouse Model Cornea with In Vivo Confocal Microscopy.

Graft-versus-host disease (GVHD) is a major complication after hematopoietic stem cell transplantation (HSCT), and ocular GVHD can cause severe dry eye disease that can lead to visual impairment. Epithelial damage, vascular invasion, corneal fibrosis, and corneal perforation may occur in severe cases. It is generally accepted that inflammatory cells such as dendritic cells and T cells contribute to this pathological condition. However, it is still unknown what pathological condition occurs on the ocular surface after HSCT, and when. We therefore observed the dynamics of inflammatory cells in the cornea of chronic GVHD (cGVHD) model mice from 1 to 4 weeks after bone marrow transplantation (BMT) by in vivo confocal microscopy (IVCM) and considered the relationship with the pathophysiology of ocular GVHD (tear volume, corneal epithelial damage). In the allogeneic group, neovascularization occurred in all eyes at 1 week after BMT, although almost all vessels disappeared at 2 weeks after BMT. In addition, we revealed that infiltration of globular cells, and tortuosity and branching of nerves in the cornea occurred in both cGVHD mice and human cGVHD patients. Thus, we consider that cGVHD mouse model study by IVCM reproduces the state of ocular GVHD and may contribute to elucidating the pathological mechanism for ocular GVHD.