Fibronectin Deposition Research Articles

Enhancing human capillary tube network assembly and maturation through upregulated expression of pericyte-derived TIMP-3.

In this study, we identify and characterize new molecular determinants that optimize human capillary tube network assembly. Our lab has previously reported a novel, serum free-defined 3D co-culture model using human endothelial cells (ECs) and human pericytes whereby EC-lined tubes form and co-assemble with pericytes, but when these cultures are maintained at or beyond 5 days, tubes become progressively wider and unstable. To address this issue, we generated novel human pericytes that carry a tissue inhibitor of metalloproteinase (TIMP)-3 transgene which can be upregulated following doxycycline addition. EC-pericyte co-cultures established in the presence of doxycycline demonstrated marked enhancement of capillary network assembly including dramatic narrowing of capillary tube widths to an average of 8µm (physiologic capillary tube width), increased tube lengths, increased tube branching, and robust stimulation of basement membrane matrix assembly, particularly with collagen type IV and fibronectin deposition compared to controls. These substantial changes depend not only on induction of pericyte TIMP-3, but also on recruitment of pericytes to EC tubes. Blockade of pericyte recruitment prevents these dramatic capillary network alterations suggesting that EC-pericyte interactions and induction of pericyte TIMP-3 are necessary together to coordinate and facilitate capillary assembly and maturation. Overall, this work is critical for our basic understanding of capillary formation, but also for the ability to reproducibly generate stabilized networks of capillary tubes.

GRHL2 regulates keratinocyte EMT-MET dynamics and scar formation during cutaneous wound healing

After cutaneous wounds successfully heal, keratinocytes that underwent the epithelial-mesenchymal transition (EMT) regain their epithelial characteristics, while in scar tissue, epidermal cells persist in a mesenchymal state. However, the regulatory mechanisms governing this reversion are poorly understood, and the impact of persistent mesenchymal-like epidermal cells in scar tissue remains unclear. In the present study, we found that during wound healing, the regulatory factor GRHL2 is highly expressed in normal epidermal cells, downregulated in EMT epidermal cells, and upregulated again during the process of mesenchymal-epithelial transition (MET). We further demonstrated that interfering with GRHL2 expression in epidermal cells can effectively induce the EMT. Conversely, the overexpression of GRHL2 in EMT epidermal cells resulted in partial reversion of the EMT to an epithelial state. To investigate the effects of failed MET in epidermal cells on skin wound healing, we interfered with GRHL2 expression in epidermal cells surrounding the cutaneous wound. The results demonstrated that the persistence of epidermal cells in the mesenchymal state promoted fibrosis in scar tissue, manifested by increased thickness of scar tissue, deposition of collagen and fibronectin, as well as the activation of myofibroblasts. Furthermore, the miR-200s/Zeb1 axis was perturbed in GRHL2 knockdown keratinocytes, and transfection with miR-200s analogs promoted the reversion of EMT in epidermal cells, which indicates that they mediate the EMT process in keratinocytes. These results suggest that restoration of the epithelial state in epidermal cells following the EMT is essential to wound healing, providing potential therapeutic targets for preventing scar formation.

Survey of Dopamine Receptor D2 Antagonists as Retinal Antifibrotics.

Purpose: To evaluate the potency and efficacy of a library of dopamine receptor D2 (D2R) antagonists in the mitigation of fibrotic activation in retinal pigment epithelial (RPE) cells. Methods: ARPE-19 cells were cultured and treated with methotrexate or 27 district D2R antagonists using a fibronectin deposition assay. The most potent compounds were then further assessed in assays measuring cellular proliferation, cellular migration, and profibrotic gene expression. Results: The previously established antifibrotic D2R antagonist loxapine exerted a robust and dose-dependent inhibition of fibronectin deposition, whereas methotrexate exerted minimal inhibition. The most potent D2R antagonist identified, fluphenazine, effectively blocked in vitro models of fibrosis at 300-1,000 nM concentrations. Conclusions: Here we found multiple FDA-approved D2R antagonists that potently block RPE cell fibrogenesis. These findings further support the potential of D2R antagonism as a potential therapeutic for retinal fibrotic disease.

Abstract A052: Silencing MICAL2 Expression in Pancreatic Cancer Cells rewires the tumor microenvironment through the IL1-a/p38 MAP kinase/STAT-3 axis and Sensitizes Tumors to Immune Checkpoint Blockade therapy

Abstract Introduction: PDAC is marked by a fibroinflammatory stroma and thrives on interactions between cancer cells and their microenvironment, including CAFs and immune cells, driving disease progression and treatment resistance. Using ChIP-seq on resected human PDAC samples, we identified MICAL2 as a super-enhancer-associated gene and its role in tumor progression. MICAL2 is a flavin monooxygenase that promotes actin depolymerization and SRF transcription. Here, we evaluated how tumor cell-expressed MICAL2 rewires the PDAC microenvironment through the IL1-a/p38 MAP kinase/STAT3 axis. Methods: KPC-Shcontrol (ShCNT) and MICAL2 (M2KD) were orthotopically injected to assess tumor growth. Sc-RNA seq, immunophenotyping, and immunohistochemistry were performed on ShCNT and M2KD tumors. Atomic force microscopy was done to assess tissue stiffness. CD8+ specific antibodies were used for T-cell depletion. Adoptive transfer of CD8+ T cells enriched from M2KD tumors was performed by tail vein injection. Anti-PD1 and anti-IL-1a antibodies were injected IP. RNA-Seq analysis was performed on human PDAC cells (AsPC-1 ShCNT and M2KD) and validation of IL-1α and IL-1R expression was done in human and mouse pancreas control, KD, OE cancer cell lines, and PSCs by q-PCR. We exposed PSCs to conditioned media from cancer cells with and without MICAL2 and checked the expression of genes related to inflammation and fibrosis by qPCR. Results: Orthotopic injections of KPC-M2KD cells led to decreased tumor growth compared to ShCNT (0.26 gm vs. 1 gm, p = 0.008). Sc-RNA and immunohistochemistry revealed reduced PDPN+ and a-SMA+ CAFs in M2KD tumors. We also observed less collagen and fibronectin deposition in M2KD tumors resulting in reduced tissue stiffness as measured by atomic force microscopy. Flow cytometry and immunofluorescence showed increased intertumoral infiltration of cytotoxic and effector CD8+T cells in M2KD tumors. CD8+T cell depletion reversed growth inhibition in M2KD tumors. Adoptive transfer of CD8+T cells enriched from M2KD tumors impeded control tumor growth. RNA-seq revealed decreased IL1-α expression in M2KD cells (p<0.05). IL1R expression was reduced on PSCs when cocultured with M2KD vs. control cell media. PSCs co-cultured with M2KD cancer cells also showed significant downregulation of genes including IL-6, Cxcl1, and LIF changes that were rescued by adding recombinant IL-1α in M2KD cells. Western blot showed MICAL2 regulates the phosphorylation of p38 MAP kinase which in turn regulates the expression of IL1-α and STAT3 activation confirmed by treating dox-inducible ShCNT and ShM2KD cancer cells with p38 inhibitor. Treating M2KD tumors with immune checkpoint blockade PD-1 alone significantly reduced tumor size and 50% of M2KD tumor-bearing mice had complete tumor regression after treatment with PD-1 and neutralizing IL-1a antibodies. Conclusion: MICAL2 mediates tumor-stromal crosstalk through the IL1-a/p38/STAT3 axis and creates an immunosuppressive environment in PDAC. MICAL2 may be a potential immunomodulatory target for pancreatic cancer therapy. Citation Format: Bharti Garg, Evangeline Mose, Edgar Esparaza, Jay Patel, Rithika Medari, Alexei Martsinkovskiy, Carrie Bishop, Gissele Gonzalez, Adam Engler, Parag Katira, Herve Tiriac, Andrew M Lowy. Silencing MICAL2 Expression in Pancreatic Cancer Cells rewires the tumor microenvironment through the IL1-a/p38 MAP kinase/STAT-3 axis and Sensitizes Tumors to Immune Checkpoint Blockade therapy [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A052.

Hypermethylation and suppression of microRNA219a-2 activates the ALDH1L2/GSH/PAI-1 pathway for fibronectin degradation in renal fibrosis

Epigenetic regulations, such as DNA methylation and microRNAs, play an important role in renal fibrosis. Here, we report the regulation of microRNA219a-2 by DNA methylation in fibrotic kidneys, unveiling the crosstalk between these epigenetic mechanisms. Through genome-wide DNA methylation analysis and pyrosequencing, we detected the hypermethylation of microRNA219a-2 in renal fibrosis induced by unilateral ureteral obstruction (UUO) or renal ischemia/reperfusion, which was accompanied by a significant decrease in microRNA-219a-5p expression. Functionally, overexpression of microRNA219a-2 enhanced fibronectin induction during hypoxia or TGF-β1 treatment of cultured renal cells. In mice, inhibition of microRNA-219a-5p suppressed fibronectin accumulation in UUO and ischemic/reperfused kidneys. Aldehyde dehydrogenase 1 family member L2 (ALDH1L2) was identified to be the direct target gene of microRNA-219a-5p in renal fibrotic models. MicroRNA-219a-5p suppressed ALDH1L2 expression in cultured renal cells, while inhibition of microRNA-219a-5p prevented the decrease of ALDH1L2 in injured kidneys. Knockdown of ALDH1L2 enhanced plasminogen activator inhibitor-1 (PAI-1) induction during TGF-β1 treatment of renal cells, which was associated with fibronectin expression. In conclusion, the hypermethylation of microRNA219a-2 in response to fibrotic stress may attenuate microRNA-219a-5p expression and induce the upregulation of its target gene ALDH1L2, which reduces fibronectin deposition by suppressing PAI-1.

Fibronectin isoforms promote postnatal skeletal development

Fibronectin (FN) is a ubiquitous extracellular matrix glycoprotein essential for the development of various tissues. Mutations in FN cause a unique form of spondylometaphyseal dysplasia, emphasizing its importance in cartilage and bone development. However, the relevance and functional role of FN during skeletal development has remained elusive. To address these aspects, we have generated conditional knockout mouse models targeting the cellular FN isoform in cartilage (cFNKO), the plasma FN isoform in hepatocytes (pFNKO), and both isoforms together in a double knockout (FNdKO). We used these mice to determine the relevance of the two principal FN isoforms in skeletal development from postnatal day one to the adult stage at two months.We identified a distinct topological FN deposition pattern in the mouse limb during different gestational and postnatal skeletal development phases, with prominent levels at the resting and hypertrophic chondrocyte zones and in the trabecular bone. Cartilage-specific cFN emerged as the predominant isoform in the growth plate, whereas circulating pFN remained excluded from the growth plate and confined to the primary and secondary ossification centers. Deleting either isoform independently (cFNKO or pFNKO) yielded only relatively subtle changes in the analyzed skeletal parameters. However, the double knockout of cFN in the growth plate and pFN in the circulation of the FNdKO mice significantly reduced postnatal body weight, body length, and bone length. Micro-CT analysis of the adult bone microarchitecture in FNdKO mice exposed substantial reductions in trabecular bone parameters and bone mineral density. The mice also showed elevated bone marrow adiposity. Analysis of chondrogenesis in FNdKO mice demonstrated changes in the resting, proliferating and hypertrophic growth plate zones, consistent alterations in chondrogenic markers such as collagen type II and X, decreased apoptosis of hypertrophic chondrocytes, and downregulation of bone formation markers. Transforming growth factor-β1 and downstream phospho-AKT levels were significantly lower in the FNdKO than in the control mice, revealing a crucial FN-mediated regulatory pathway in chondrogenesis and bone formation.In conclusion, the data demonstrate that FN is essential for chondrogenesis and bone development. Even though cFN and pFN act in different regions of the bone, both FN isoforms are required for the regulation of chondrogenesis, cartilage maturation, trabecular bone formation, and overall skeletal growth.

Repurposing nitrofurantoin as a stimulant of fibroblast extracellular matrix repair for the treatment of emphysema

Emphysema is a respiratory disease that causes the progressive loss of lung extracellular matrix (ECM) organisation, subsequently undermining lung integrity and reducing lung function. Fibroblasts must constantly repair damage to the lungs to preserve lung health, however, fibroblast ECM repair is reduced during emphysema, causing ECM damage to outweigh fibroblast ECM maintenance. Current treatments for emphysema fail to address the root causes of emphysematous progression, highlighting the need for novel methods of treating emphysema. Nitrofurantoin is a broad-spectrum antibiotic indicated for the treatment of urinary tract infections that also displays potential as a novel avenue of emphysema treatment. Nitrofurantoin is known to potentially cause fibrotic effects that could be repurposed to increase fibroblast repair and outweigh the progressive ECM damage of the emphysematous lung. Therefore, this study examined the effects of nitrofurantoin treatment on primary human lung fibroblasts derived from emphysema patients to determine if the drug holds potential as a novel treatment for emphysema. Nitrofurantoin was shown to stimulate migration and alter fibroblast morphology by increasing cell area and reducing roundness, suggesting that it could induce an ECM-repair primed phenotype in fibroblasts. Interestingly, nitrofurantoin treatment did not alter collagen-IV, perlecan, periostin or tenascin-C deposition, though fibronectin deposition was significantly upregulated at a higher dosage (20 μg/mL). This study highlighted the nitrofurantoin induced changes to fibroblast motility and morphology that facilitate ECM repair. Thus, nitrofurantoin induced pulmonary fibrosis could be caused by a change in cell phenotype that subsequently upregulates ECM repair, indicating its potential as a treatment for emphysema.

Zinc Iodide Dimethyl Sulfoxide Reduces Collagen Deposition by Increased Matrix Metalloproteinase-2 Expression and Activity in Lung Fibroblasts.

Chronic inflammatory lung diseases are characterized by disease-specific extracellular matrix accumulation resulting from an imbalance of matrix metalloproteinases (MMPs) and their inhibitors. Zinc is essential for the function of MMPs, and zinc deficiency has been associated with enhanced tissue remodeling. This study assessed if zinc iodide (ZnI) supplementation through dimethyl sulfoxide (DMSO) modifies the action of MMPs in isolated human lung fibroblasts. The expression and activity of two gelatinases, MMP-2 and MMP-9, were determined by gelatin zymography and enzyme-linked immuno-sorbent assay (ELISA). Collagen degradation was determined by cell-based ELISAs. Collagen type I and fibronectin deposition was stimulated by human recombinant tumor growth factor β1 (TGF-β1). Untreated fibroblasts secreted MMP-2 but only minute amounts of MMP-9. TGF-β1 (5 ng/mL) reduced MMP-2 secretion, but stimulated collagen type I and fibronectin deposition. All the effects of TGF-β1 were significantly reduced in cells treated with ZnI-DMSO over 24 h, while ZnI and DMSO alone had a lower reducing effect. ZnI-DMSO alone did not increase MMP secretion but enhanced the ratio of active to inactive of MMP-2. ZnI alone had a lower enhancing effect than ZnI-DMSO on MMP activity. Furthermore, MMP-2 activity was increased by ZnI-DMSO and ZnI in the absence of cells. Soluble collagen type I increased in the medium of ZnI-DMSO- and ZnI-treated cells. Blocking MMP activity counteracted all the effects of ZnI-DMSO. Conclusion: The data suggest that the combination of ZnI with DMSO reduces fibrotic processes by increasing the degradation of collagen type I by up-regulating the activity of gelatinases. Thus, the combination of ZnI with DMSO might be considered for treatment of fibrotic disorders of the lung. DMSO supported the beneficial effects of ZnI.

Preclinical evaluation of combined therapy with amiodarone and low-dose benznidazole in a mouse model of chronic Trypanosoma cruzi infection

Chagasic chronic cardiomyopathy (CCC) is the primary clinical manifestation of Chagas disease (CD), caused by Trypanosoma cruzi. Current therapeutic options for CD are limited to benznidazole (Bz) and nifurtimox. Amiodarone (AMD) has emerged as most effective drug for treating the arrhythmic form of CCC. To address the effects of Bz and AMD we used a preclinical model of CCC. Female C57BL/6 mice were infected with T. cruzi and subjected to oral treatment for 30 consecutive days, either as monotherapy or in combination. AMD in monotherapy decreased the prolonged QTc interval, the incidence of atrioventricular conduction disorders and cardiac hypertrophy. However, AMD monotherapy did not impact parasitemia, parasite load, TNF concentration and production of reactive oxygen species (ROS) in cardiac tissue. Alike Bz therapy, the combination of Bz and AMD (Bz/AMD), improved cardiac electric abnormalities detected T. cruzi-infected mice such as decrease in heart rates, enlargement of PR and QTc intervals and increased incidence of atrioventricular block and sinus arrhythmia. Further, Bz/AMD therapy ameliorated the ventricular function and reduced parasite burden in the cardiac tissue and parasitemia to a degree comparable to Bz monotherapy. Importantly, Bz/AMD treatment efficiently reduced TNF concentration in the cardiac tissue and plasma and had beneficial effects on immunological abnormalities. Moreover, in the cardiac tissue Bz/AMD therapy reduced fibronectin and collagen deposition, mitochondrial damage and production of ROS, and improved sarcomeric and gap junction integrity. Our study underlines the potential of the Bz/AMD therapy, as we have shown that combination increased efficacy in the treatment of CCC.

Abstract PO2-25-07: PEGylated Functional Upstream Domain (PEG-FUD): an anti-cancer therapy for breast Cancer

Abstract Background: Breast cancer (BC) is the most common cancer diagnosed in women. In breast cancers, the extracellular matrix (ECM) is known to play a key role in disease progression by mediating cell signaling processes that drive cancer cell proliferation, migration and invasion. Work by our group identified that aligned collagen fibers perpendicular to the tumor boundary are prognostic of poor patient prognosis. Further, through matrix targeted proteomics we determined that the ECM protein, Fibronectin (FN), organizes with aligned collagen fibers in BC tissues. FN is known as the master regulator of ECM assembly because FN deposition precedes and regulates the deposition of several other ECM proteins. Clinical evidence shows that high expression of FN levels in BC patients correlates with an increased mortality risk. Due to the abundant expression of FN in the tumor microenvironment, FN has been a useful biomarker for cancer imaging and therapy. Despite multiple efforts in developing therapies that target the ECM, currently there are no effective ECM treatments available due to toxicity and lack of specificity. Methods: To target abnormal FN deposition, we used a FN binding peptide, Functional Upstream Domain (FUD), derived from the F1 adhesin from Streptococcus pyogenes. PEGylated-FUD (PEG-FUD) is a potent inhibitor of FN assembly which binds the 70 kDa N-terminal region of FN with high affinity. We hypothesize that PEG-FUD will localize to the tumor site and that targeted disruption of FN assembly with PEG-FUD will reduce ECM deposition, thus block tumor progression in-vivo. In this study, we used an in vivo imaging system to assess the biodistribution of 20-kDa PEG-FUD following subcutaneous injection of Cy5 labeled peptide in 4T1 mammary tumor bearing mice. Additionally, in a second therapeutic experiment, we treated 4T1 mammary tumor bearing mice with 20-kDa PEG-FUD every 48 hr for a total of 10 treatments and measured tumor volume as an indicator of primary tumor burden. Results: As anticipated, we observed PEG-FUD’s accumulation and localization in 4T1 tumors. Additionally, PEG-FUD treatment significantly reduced tumor growth compared to saline treatment. There were no observed changes in standard toxicity assessments such as body weight and spleen weight among treatment groups. After PEG-FUD’s therapeutic treatment, we observed a significant reduction in the deposition of FN matrix and an increase in cleaved caspase-3, a known marker for apoptosis by western blotting providing a potential mechanism of action of PEG-FUD inducing changes in tumor growth. Conclusions: PEG-FUD’s localization in tumors suggests its utility as a solo cancer imaging agent while providing indications that PEG-FUD can be used to deliver other therapeutics to the tumor site as a conjugate in the future. In addition, therapeutic treatment of PEG-FUD inhibited tumor growth providing preliminary evidence for PEG-FUD’s use as a tumor targeting anti-cancer agent. Citation Format: Metti Gari. PEGylated Functional Upstream Domain (PEG-FUD): an anti-cancer therapy for breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-25-07.

Abstract PO4-24-07: The Impact of GPER Modulation on Cancer Associated Fibroblasts on Extracellular Matrix Formation in Breast Cancer

Abstract Background: The G-protein coupled estrogen receptor (GPER) is a noncanonical estrogen receptor (ER) that is estimated to be present in roughly 50-60% of all breast cancer (BC) subtypes. Previous studies have suggested that the presence of GPER during primary disease aids in disease progression, metastasis, as well as chemotherapy resistance due to the agonistic activity of traditional chemotherapies for ER+ BC, tamoxifen and fulvestrant. It is also well established that the extracellular matrix (ECM), specifically collagen, contributes to the overall risk and progression of BC in patients. Importantly, fibroblasts are one of the primary cell types responsible for ECM deposition in the tumor microenvironment. We hypothesize that the modulation of cancer-associated fibroblasts (CAFs) via estrogen signaling through GPER regulates the deposition and structure of key ECM proteins, such as collagen, to aid in disease progression. Methods: CAFs, isolated from human BC surgical resections, were plated at 100% confluency, and incubated with either 10nM β-estradiol (E2), 50nM G1 (a GPER specific agonist) or a vehicle control and 50ug/mL ascorbic acid daily for 14 days to induce matrix deposition. Phenol-free, high glucose DMEM with 10% charcoal stripped FBS was used as media to reduce FBS sourced estrogen. Following the 14-day incubation, cell proliferation was quantified prior to extracting the cells to isolate the CAF-derived matrix (CDM). The organization and composition of ECM was analyzed in CDMs through immunofluorescence (IF) or western blot, respectively. An unpaired t-test was conducted on biological triplicates and between vehicle control and either G1 or E2. Significance was determined as p< 0.05. Results: Culturing CAFs with E2 resulted in a 10% increase in cell proliferation (n=3, p< 0.05) and a 1.6-fold (n=3, p< 0.05) increase in total ECM deposition by western blot. Key ECM proteins such as collagen, fibronectin, and periostin had a 1.8, 1.3, and 1.3-fold increase, respectively (n=3, p< 0.05), in protein deposition with E2 treatment when normalized to cell number. Collagen fiber analysis of IF stained CDM for collagen resulted in a coefficient of alignment with E2 of 0.76 compared to 0.51 without (n=3 for E2 and n=6 for vehicle, p< 0.05). To confirm E2 was acting through GPER, CDMs were subsequently generated with exposure to 50nM G1, a specific GPER agonist. Collagen fiber analysis of the G1 exposed CDMs resulted in a coefficient of alignment with G1 of 0.71 compared to 0.51 without (n=3 for G1 and n=6 for vehicle, p< 0.05). Conclusions: This study demonstrates that estrogen signaling through GPER modulates the deposition of fibronectin, periostin, and collagen as well as the organization of collagen architecture. These results highlight the need to further investigate how the interplay between the ECM, GPER activity, and fibroblasts impacts breast cancer progression. Citation Format: Shelby Fertal, Brian Burkel, Fern Murdoch, Kathy O'Leary, Linda Schuler, Suzanne Ponik. The Impact of GPER Modulation on Cancer Associated Fibroblasts on Extracellular Matrix Formation in Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-24-07.

Prolonged Antibiotic Use in Gulf War Chronic Multisymptom Illness Induces Renal Fibrosis-Like Pathology Associated with microRNA-21-Mediated PTEN Inhibition

Gulf War veterans afflicted with chronic multisymptom Illness (GWI) often experience unexplained, debilitating symptoms, including microbiome dysbiosis, gastrointestinal and neuroinflammation. Prolonged antibiotic treatments, especially of fluoroquinolone class are commonly employed in these veterans, raising concerns about their potential side effects. To date, no studies have investigated the effects of Gulf War (GW) chemicals- Pyridostigmine bromide (PB) and insecticide, permethrin exposures on renal dysfunction in the veterans. Therefore, this study aimed to investigate the impact of prolonged antibiotic exposure on renal pathology in GWI and to elucidate the underlying molecular mechanisms leading to renal dysfunction. In this study, we used a persistent Gulf War Illness (GWI) mouse model to study the combined effect of prolonged antibiotic regimen involving Neomycin and Enrofloxacin treatment for 5 months (20 weeks). Our results showed that prolonged antibiotic treatment exacerbated renal inflammation leading to elevated levels of pro- inflammatory cytokines and significant activation of NF-κB signaling over Gulf war chemicals treated (GWI) mice (GWI). Further, we hypothesized the involvement of HMGB1 mediated RAGE activation leading to the inflammatory phenotype in the kidneys of GWI+ AB mice. We observed that prolonged antibiotic exposure in GWI- induced mice led to significant increased HMGB1-mediated RAGE activation compared to GWI mice, which was associated with increased TGF-β production in GWI+ AB mice. Furthermore, miR-21, whose expression is reported to be regulated by TGF-β is widely linked to renal fibrosis, was also significantly upregulated in antibiotic-treated GWI-induced mice. This upregulation was associated with decreased PTEN expression, a direct target of miR-21 in GWI+ AB mice over GWI- mice, resulting in the activation of the AKT signaling pathway and increased extracellular matrix (ECM) deposition in GWI+ AB mice. Furthermore, we examined the involvement of AKT signaling activation in the induction of Epithelial-Mesenchymal Transition (EMT) by assessing the immunoreactivity of α-SMA. The renal tissue of GWI+AB mice exhibited an elevated immunoreactivity of α-SMA, suggesting that the cells were undergoing transition from an epithelial to a mesenchymal state. In contrast, GWI- mice displayed no significant expression of α-SMA or increased fibronectin deposition, indicating that exposure to Gulf War chemicals alone was insuffcient to induce renal fibrosis-like pathology. These findings highlight the complex interplay between GWI, antibiotics, and renal pathology, emphasizing that prolonged antibiotic treatment in Gulf War Chronic Multisymptom Illness leads to renal fibrosis like- pathology by activating TGF- β dependent miR-21/ PTEN/ AKT signaling. This study was supported by VA Merit Award I01CX001923-01 awarded to Dr. Saurabh Chatterjee. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

64Cu]Cu-PEG-FUD peptide for noninvasive and sensitive detection of murine pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease resulting in irreversible scarring within the lungs. However, the lack of biomarkers that enable real-time assessment of disease activity remains a challenge in providing efficient clinical decision-making and optimal patient care in IPF. Fibronectin (FN) is highly expressed in fibroblastic foci of the IPF lung where active extracellular matrix (ECM) deposition occurs. Functional upstream domain (FUD) tightly binds the N-terminal 70-kilodalton domain of FN that is crucial for FN assembly. In this study, we first demonstrate the capacity of PEGylated FUD (PEG-FUD) to target FN deposition in human IPF tissue ex vivo. We subsequently radiolabeled PEG-FUD with 64Cu and monitored its spatiotemporal biodistribution via μPET/CT imaging in mice using the bleomycin-induced model of pulmonary injury and fibrosis. We demonstrated [64Cu]Cu-PEG-FUD uptake 3 and 11 days following bleomycin treatment, suggesting that radiolabeled PEG-FUD holds promise as an imaging probe in aiding the assessment of fibrotic lung disease activity.

Dipeptidyl Peptidase-4–Mediated Fibronectin Processing Evokes a Profibrotic Extracellular Matrix

Fibronectin serves as a platform to guide and facilitate deposition of collagen and fibrillin microfibrils. During development of fibrotic diseases, altered fibronectin deposition in the extracellular matrix (ECM) is generally an early event. Following this, dysregulated organization of fibrillins and fibrillar collagens occurs. Because fibronectin is an essential orchestrator of healthy ECM, perturbation of its ECM-organizational capacity may be involved in development of fibrosis. To investigate this, we employed recessive dystrophic epidermolysis bullosa (RDEB) as a disease model with progressive, severe dermal fibrosis. Fibroblasts from RDEB donors in 2D and 3D cultures displayed dysregulated fibronectin deposition. Our analyses revealed that increase of pro-fibrotic DPP4+ fibroblasts coincides with altered fibronectin deposition. DPP4 inhibitors normalized deposition of fibronectin and subsequently of fibrillin microfibrils and collagen I. Intriguingly, proteomics, inhibitor and mutagenesis studies disclosed that DPP4 modulates ECM deposition through proteolysis of the fibronectin N-terminus. Our study provides mechanistic insights to the observed pro-fibrotic activities of DPP4 and extends the understanding of fibronectin-guided ECM assembly in health and disease.

Targeting ROCK2 improves macromolecular permeability in a 3D fibrotic pancreatic cancer microenvironment model

Pancreatic cancer is characterized by a densely fibrotic stroma. The fibrotic stroma hinders the intratumoral penetration of nanomedicine and diminishes therapeutic efficacy. Fibrosis is characterized by an abnormal organization of extracellular matrix (ECM) components, namely the abnormal deposition and/or orientation of collagen and fibronectin. Abnormal ECM organization is chiefly driven by pathological signaling in pancreatic stellate cells (PSCs), the main cell type involved in fibrogenesis. However, whether targeting signaling pathways involved in abnormal ECM organization improves the intratumoral penetration of nanomedicines is unknown. Here, we show that targeting transforming growth factor-β (TGFβ)/Rho-associated kinase (ROCK) 1/2 signaling in PSCs normalizes ECM organization and concomitantly improves macromolecular permeability of the fibrotic stroma. Using a 3-dimensional cell culture model of the fibrotic pancreatic cancer microenvironment, we found that pharmacological inhibition of TGFβ or ROCK1/2 improves the permeation of various macromolecules. By using an isoform-specific pharmacological inhibitor and siRNAs, we show that targeting ROCK2, but not ROCK1, alone is sufficient to normalize ECM organization and improve macromolecular permeability. Moreover, we found that ROCK2 inhibition/knockdown attenuates Yes-associated protein (YAP) nuclear localization in fibroblasts co-cultured with pancreatic cancer cells in 3D. Finally, pharmacological inhibition or siRNA-mediated knockdown of YAP normalized ECM organization and improved macromolecular permeability. Our results together suggest that the TGFβ/ROCK2/YAP signaling axis may be therapeutically targeted to normalize ECM organization and improve macromolecular permeability to augment therapeutic efficacy of nanomedicines in pancreatic cancer.

Akt-driven TGF-β and DKK1 Secretion Impairs F508del CF Airway Epithelium Polarity.

Epithelial polarity is fundamental in maintaining barrier integrity and tissue protection. In cystic fibrosis (CF), apicobasal polarity of the airway epithelium is altered, resulting in increased apical fibronectin deposition and enhanced susceptibility to bacterial infections. Here, we evaluated the effect of highly effective modulator treatment (HEMT) on fibronectin apical deposition and investigated the intracellular mechanisms triggering the defect in polarity of the CF airway epithelium. To this end, primary cultures of CF (F508del variant) human airway epithelial cells (HAECs) and a HAEC line, Calu-3, knocked-down (KD) for CFTR (CFTR KD) were compared to control counterparts, grown at an air-liquid interface (ALI). We show that CFTR mutation in primary HAECs and CFTR KD cells promote the overexpression and over-secretion of TGF-β1 and DKK1 when cultured at ALI. These dynamic changes result in hyperactivation of the TGF-β pathway and inhibition of the Wnt pathway through degradation of β-catenin leading to imbalanced proliferation and polarization. The abnormal interplay between TGF-β and Wnt signaling pathways is reinforced by aberrant Akt signaling. Pharmacological manipulation of TGF-β, Wnt, and Akt pathways restored polarization of the F508del CF epithelium, a correction that was not achieved by HEMT. Our data shed new insights into the signaling pathways that fine-tune apicobasal polarization in primary airway epithelial cells and may provide an explanation to the mitigated efficacy of HEMT on lung infection in people with CF.

THE PATHOGENIC ROLE OF MICROBIAL TRIMETHYLAMINE IN IBD ASSOCIATED INTESTINAL FIBROSIS

Abstract INTRODUCTION Intestinal fibrosis significantly contributes to the burden of inflammatory bowel diseases (IBD). No specific anti-fibrotic therapy is available. Two modifiable risk factors that may be exploited to limit fibrosis in IBD are the diet and gut microbiome. In the metaorganismal metabolism model, microbes metabolize dietary components to primary metabolites that may themselves signal through host receptor systems or be further metabolized to secondary metabolites by other microbes or host enzymes to exert a physiological or pathophysiological effect. We hypothesize that gut microbes profoundly influence intestinal fibrosis through small molecule metabolites and may provide novel targets to address the fibrotic burden in IBD. METHODS To understand how the trimethylamine-N-oxide (TMAO) pathway is affected by inflammation in the intestine, LC-MS was used to quantitate a dietary precursor, choline, primary microbial metabolite, trimethylamine (TMA), and secondary metabolite, TMAO, in mice subjected to acute DSS colitis. The cellular effects of choline, TMA, and TMAO on the deposition of fibronectin and collagen I were quantitated in primary human intestinal myofibroblasts (HIMFs). Single cell RNA-sequencing (scRNA-seq) data were interrogated to determine whether expression of the TMA-to-TMAO converting enzyme, FMO3, was downregulated in human intestinal cells of Crohn’s disease patients. RESULTS Acute DSS colitis showed increased TMA and reduced levels of TMAO, in colon tissue, which is consistent with reduced TMA-to-TMAO conversion by FMO3. Additionally, TMA was increased in intestinal contents, which suggests that microbial production of TMA from choline may also be upregulated during intestinal inflammation. In HIMFs, TMA, but not its dietary precursor, choline, nor the secondary metabolite, TMAO, increased the deposition of the extracellular matrix proteins fibronectin and collagen I. scRNA-seq analysis of the mesenchymal compartment of human intestine revealed expression of FMO3 specifically in the fibroblast cluster and downregulation of this expression in Crohn’s disease (CD) strictures compared to controls, an observation that could contribute to TMA accumulation in vivo. CONCLUSION TMA is increased in experimental colitis and activates fibroblasts towards a pro-fibrogenic phenotype. This may be mediated by reduced levels of FMO3. We next aim to measure TMAO pathway metabolites in human tissues, functionally block the TMAO pathway in vivo, and explore TMA signaling through its putative receptor, trace amine-associated receptor 5 (TAAR5). Diet-microbe-host interaction pathways represent an untapped opportunity for therapeutic intervention in multiple human disease states, such as inflammatory bowel diseases (IBD).

Downregulation of the kidney glucagon receptor, essential for renal function and systemic homeostasis, contributes to chronic kidney disease

The glucagon receptor (GCGR) in the kidney is expressed in nephron tubules. In humans and animal models with chronic kidney disease, renal GCGR expression is reduced. However, the role of kidney GCGR in normal renal function and in disease development has not been addressed. Here, we examined its role by analyzing mice with constitutive or conditional kidney-specific loss of the Gcgr. Adult renal Gcgr knockout mice exhibit metabolic dysregulation and a functional impairment of the kidneys. These mice exhibit hyperaminoacidemia associated with reduced kidney glucose output, oxidative stress, enhanced inflammasome activity, and excess lipid accumulation in the kidney. Upon a lipid challenge, they display maladaptive responses with acute hypertriglyceridemia and chronic proinflammatory and profibrotic activation. In aged mice, kidney Gcgr ablation elicits widespread renal deposition of collagen and fibronectin, indicative of fibrosis. Taken together, our findings demonstrate an essential role of the renal GCGR in normal kidney metabolic and homeostatic functions. Importantly, mice deficient for kidney Gcgr recapitulate some of the key pathophysiological features of chronic kidney disease.

Abstract A039: Silencing MICAL2 expression in pancreatic cancer cells reduces IL-1A expression and inhibits tumor growth through a CD8+ T cell dependent mechanism

Abstract Introduction: Pancreatic cancer is characterized by desmoplastic, fibroinflammatory stroma. The crosstalk between cancer cells and their surrounding tumor microenvironment (TME) promotes disease progression, metastasis, and chemoresistance. We identified MICAL2 as a super-enhancer-associated gene in pancreatic cancer. MICAL2 (molecule interacting with Cas-L) proteins are flavin monooxygenases that promote actin depolymerization and indirectly regulate SRF transcription. In other work, we have found that MICAL2 promotes pancreatic cancer growth and progression. This study evaluated how MICAL2 pancreatic cancer cell expression modulates the PDAC tumor microenvironment. Methods: RNA-Seq analysis performed on human pancreas cancer cells (AsPC-1) before and after MICAL2 KD revealed differential regulation of IL-1α. We validated the expression of IL-1α in multiple human and mouse pancreas cancer cell lines by q-PCR. We next exposed human (h) and mouse (m) PSCs to conditioned media (CM) from cancer cells before and after MICAL2 KD and checked the expression of a-SMA, fibronectin, and Col1A and IL-6 genes by qPCR. KrasG12D/+; Trp53R172H/+; Pdx1-cre (KPC) cells with and without MICAL2 were orthotopically injected to assess the in vivo tumor growth and metastasis. Sc-RNA seq and Immunophenotyping were performed on Shcontrol (ShCNT) and MICAL2 (M2KD) KD tumors. CD8+ T cell depletion was done using an antibody-mediated approach. The adoptive transfer of CD8+ T cells extracted from MICAL2 KD tumors was done by tail vein injection. Results: MICAL2 KD resulted in the downregulation of the IL-1α gene in both human and mouse pancreas cancer cell lines (50% reduction, p<0.05). Human and mouse pancreatic stellate cells (hPSCs and mPSCs) co-cultured with cancer cells CM showed significant downregulation of a-SMA, fibronectin, Col1A, and IL-6 upon MICAL2 KD as compared to hPSCs and mPSCs co-cultured with ShCNT cells. Orthotopic injections of KPC MICAL2 KD cells led to decreased tumor growth as compared to ShCNT (0.26 gm vs. 1 gm, p = 0.008). Immunofluorescence (IF) revealed less α-SMA, PDGF-α, and IL-6 expression and reduced deposition of collagen and fibronectin in MICAL2 KD tumors. Single-cell RNA seq and flow cytometry studies of tumors harvested from both groups showed significantly increased infiltration of activated cytotoxic CD8+ T cells in MICAL2 KD tumors which was further confirmed by IF. Antibody-mediated depletion of CD8+ T cells in MICAL2 KD tumors abrogated their reduced tumor growth in both immune-hot and immune-cold KPC cell lines. Adoptive transfer of CD8+ T cells extracted from M2KD tumors significantly reduced ShCNT flank tumor growth. Conclusion: These data reveal that MICAL2 expression mediates tumor-stromal crosstalk through IL1A and creates an immunosuppressive environment in PDAC and suggests MICAL2 may be an attractive immunomodulatory target for pancreatic cancer therapy. Ongoing work is focused on dissecting the role of MICAL2 in priming the metastatic niche through the remodeling of the TME. Citation Format: Bharti Garg, EvanGeline Mose, Edgar Esparza, Jay Patel, Sarah Sass, Alexei Martsinkovskiy, Dawn Jacquish, Herve Tiriac, Andrew M. Lowy. Silencing MICAL2 expression in pancreatic cancer cells reduces IL-1A expression and inhibits tumor growth through a CD8+ T cell dependent mechanism [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A039.

Leech extract alleviates idiopathic pulmonary fibrosis by TGF-β1/Smad3 signaling pathway

Ethnopharmacological relevanceLeech, as a traditional Chinese medicine for the treatment of blood circulation and blood stasis, was also widely used to cure pulmonary fibrosis in China. In clinical practice, some traditional Chinese medicine preparation such as Shui Zhi Xuan Bi Hua Xian Tang and Shui Zhi Tong Luo Capsule composed of leech, could improve the clinical symptoms and pulmonary function in patients with idiopathic pulmonary fibrosis (IPF). However, the material basis of the leech in the treatment of IPF were not yet clear. Aim of the studyScreen out the components of leech that have the anti-pulmonary fibrosis effects, and further explore the therapeutic mechanism of the active components. Materials and methodsIn this study, the different molecular weight components of leech extract samples were prepared using the semi-permeable membranes with different pore sizes. The therapeutic effects of the leech extract groups with molecular weight greater than 10 KDa (>10 KDa group), between 3 KDa and 10 KDa (3–10 KDa group), and less than 3 KDa (<3 KDa group) on pulmonary fibrosis were firstly investigated by cell proliferation and cytotoxicity assay (MTT), cell wound healing assay, immunofluorescence staining (IF) and Western blot (WB) assay through the TGF-β1-induced fibroblast cell model. Then bleomycin-induced pulmonary fibrosis (BML-induced PF) mouse model was constructed to investigate the pharmacological activities of the active component group of leech extract in vivo. Pathological changes of the mouse lung were observed by hematoxylin-eosin staining (H&E) and Masson's trichrome staining (Masson). The hydroxyproline (HYP) content of lung tissues was quantified by HYP detection kit. The levels of extracellular matrix-related fibronectin (FN) and collagen type Ⅰ (Collagen Ⅰ), pyruvate kinase M2 (PKM2) monomer and Smad7 protein were determined via WB method. PKM2 and Smad7 protein were further characterized by IF assays. ResultsUsing TGF-β1-induced HFL1 cell line as a PF cell model, the in vitro results demonstrated that the >10 KDa group could significantly inhibited the cell proliferation and migration, downregulated the expression level of cytoskeletal protein vimentin and α-smooth muscle actin (α-SMA), and reduced the deposition of FN and Collagen Ⅰ. In the BML-induced PF mouse model, the >10 KDa group significantly reduced the content of HYP, downregulated the expression levels of FN and Collagen Ⅰ in lung tissues, and delayed the pathological changes of lung tissue structure. The results of WB and IF assays further indicated that the >10 KDa group could up-regulate the expression level of PKM2 monomer and Smad7 protein in the cellular level, thereby delaying the progression of pulmonary fibrosis. ConclusionsOur study revealed that the >10 KDa group was the main material basis of the leech extract that inhibited pulmonary fibrosis through TGF-β1/Smad3 signaling pathway.