Immunosuppressive Potential Research Articles

RapaLink-1 outperforms rapamycin in alleviating allogeneic graft rejection by inhibiting the mTORC1-4E-BP1 pathway in mice

Inhibition of mammalian target of rapamycin (mTOR), which is a component of both mTORC1 and mTORC2, leads to clinical benefits for organ transplant recipients. Pathways to inhibit mTOR include strengthening the association of FKBP12-mTOR or competing with ATP at the active site of mTOR, which have been applied to the design of first- and second-generation mTOR inhibitors, respectively. However, the clinical efficacy of these mTOR inhibitors may be limited by side effects, compensatory activation of kinases and attenuation of feedback inhibition of receptor expression. A new generation of mTOR inhibitors possess a core structure similar to rapamycin and covalently link to mTOR kinase inhibitors, resulting in moderate selectivity and potent inhibition of mTORC1. Since the immunosuppressive potential of this class of compounds remains unknown, our goal is to examine the therapeutic efficacy of a third-generation mTOR inhibitor in organ transplantation. In this study, RapaLink-1 outperformed rapamycin in inhibiting T-cell proliferation and significantly prolonged graft survival time. Mechanistically, the ameliorated rejection induced by RapaLink-1 is associated with a reduction in p-4E-BP1 in T cells, resulting in an elevation in Treg cells alongside a decline in Th1 and Th17 cells. For the first time, these studies demonstrate the effectiveness of third-generation mTOR inhibitors in inhibiting allograft rejection, highlighting the potential of this novel class of mTOR inhibitors for further investigation.

Rheumatoid Synovial Fluid and Acidic Extracellular pH Modulate the Immunomodulatory Activity of Urine-Derived Stem Cells.

Urine-derived stem cells (UdSCs) possess a remarkable anti-inflammatory and immune-modulating activity. However, the clinical significance of UdSCs in autoimmune inflammatory diseases such as rheumatoid arthritis (RA) is yet to be explored. Hence, we tested the UdSCs response to an articular RA microenvironment. To simulate the inflamed RA joint more authentically in vitro, we treated cells with rheumatoid synovial fluids (RASFs) collected from RA patients, serum deprivation, acidosis (pH 7.0 and 6.5), and their combinations. Firstly, the RASFs pro-inflammatory status was assessed by cytokine quantification. Then, UdSCs were exposed to the RA environmental factors for 48 h and cell proliferation, gene expression and secretion of immunomodulatory factors were evaluated. The immunosuppressive potential of pre-conditioned UdSCs was also assessed via co-cultivation with activated peripheral blood mononuclear cells (PBMCs). In all experimental conditions, UdSCs' proliferation was not affected. Conversely, extracellular acidosis considerably impaired the viability/proliferation of adipose tissue-derived stem cells (ATSCs). In the majority of cases, exposure to RA components led to the upregulated expression of IL-6, TSG6, ICAM-1, VCAM-1, and PD-L1, all involved in immunomodulation. Upon RASFs and acidic stimulation, UdSCs secreted higher levels of immunomodulatory cytokines: IL-6, IL-8, MCP-1, RANTES, GM-CSF, and IL-4. Furthermore, RASFs and combined pretreatment with RASFs and acidosis promoted the UdSCs-mediated immunosuppression and the proliferation of activated PBMCs was significantly inhibited. Altogether, our data indicate that the RA microenvironment certainly has the capacity to enhance UdSCs' immunomodulatory function. For potential preclinical/clinical applications, the intra-articular injection might be a reasonable approach to maximize UdSCs' therapeutic efficiency in the RA treatment.

Canine immune cells express high levels of CB1 and CB2 cannabinoid receptors and cannabinoid-mediated alteration of canine cytokine production is vehicle-dependent

With the increased popularity and societal acceptance of marijuana and cannabidiol (CBD) use in humans, there is an interest in using cannabinoids in veterinary medicine. There have been a few placebo-controlled clinical trials in dogs suggesting that cannabis-containing extracts are beneficial for dogs with inflammatory diseases such as osteoarthritis, and there is growing interest in their immunosuppressive potential for the treatment of immune-mediated diseases. Since cannabinoids exhibit anti-inflammatory and immunosuppressive effects in many species, the purpose of these studies was to examine whether the plant-derived cannabinoids, CBD and Δ9-tetrahydrocannabinol (THC), would also suppress immune function in canine peripheral blood mononuclear cells (PBMCs). Another goal was to characterize expression of the cannabinoid receptors, CB1 and CB2, in canine immune cells. We hypothesized that CBD and THC would suppress stimulated cytokine expression and that both cannabinoid receptors would be expressed in canine immune cells. Surprisingly, cannabinoid suppressive effects in canine PMBCs were quite modest, with the most robust effect occurring at early stimulation times and predominantly by THC. We further showed that cannabinoid-mediated suppression was dog- and vehicle-dependent with CBD and THC delivered in dimethyl sulfoxide (DMSO) producing more immune suppressive effects as compared to ethanol (ETOH). PCR, flow cytometry, and immunohistochemical staining demonstrated that both CB1 and CB2 are expressed in canine immune cells. Together these data show that canine immune cells are sensitive to suppression by cannabinoids, but more detailed studies are needed to further understand the mechanisms and broad effects of these compounds in the dog.

Adiponectin restores the obesity-induced impaired immunomodulatory function of mesenchymal stromal cells via glycolytic reprogramming

Obesity has been known to negatively modulate the life-span and immunosuppressive potential of mesenchymal stromal cells (MSC). However, it remains unclear what drives the compromised potency of obese MSC. In this study, we examined the involvement of adiponectin, an adipose tissue-derived hormone, in obesity-induced impaired therapeutic function of MSC. Diet-induced obesity leads to a decrease in serum adiponectin, accompanied by impairment of survival and immunomodulatory effects of adipose-derived MSC (ADSC). Interestingly, priming with globular adiponectin (gAcrp) improved the immunomodulatory potential of obese ADSC. Similar effects were also observed in lean ADSC. In addition, gAcrp potentiated the therapeutic effectiveness of ADSC in a mouse model of DSS-induced colitis. Mechanistically, while obesity inhibited the glycolytic capacity of MSC, gAcrp treatment induced a metabolic shift toward glycolysis through activation of adiponectin receptor type 1/p38 MAPK/hypoxia inducible factor-1α axis. These findings suggest that activation of adiponectin signaling is a promising strategy for enhancing the therapeutic efficacy of MSC against immune-mediated disorders.

Oxidative stress is involved in immunosuppression and macrophage regulation in glioblastoma

Oxidative stress dually affected cancer progression, while its effect on glioblastomas remained unclear. Herein, we clustered the multicenter glioblastoma cohorts based on the oxidative-stress-responsive genes (OSS) expression. We found that cluster 2 with high OSS levels suffered a worse prognosis. Functional analyses and immune-related analyses results exhibited that M2-like pro-tumoral macrophages and neutrophils were enriched in cluster 2, while Natural killer cells' infiltration was decreased. The increased M2-like pro-tumoral macrophages in cluster 2 was confirmed by immunofluorescence. An integrated single-cell analysis validated the malignant features of cluster 2 neoplastic cells and discovered their crosstalk with M2-like pro-tumoral macrophages. Moreover, we observed that SOD3 knockdown might decrease the M2-like pro-tumoral transformation of macrophage in vitro and in vivo. Comprehensively, we revealed oxidative stress' prognostic and immunosuppressive potential in glioblastoma and discovered SOD3's potential role in regulating macrophage M2-like pro-tumoral transformation.

Immunomodulatory effects of mesenchymal stem cells on B and T cells

Mesenchymal stem cells (MSCs) or adult multipotent progenitor cells with the ability to self-renew and differentiate, are extracted from a variety of tissues, including bone marrow, adipose tissue, umbilical cord blood, Wharton’s jelly, tooth pulp, menstrual blood, and others. Since they are multipotent, cultured MSCs can differentiate into the adipogenic, chondrogenic, and osteogenic lineages after being isolated. Due to their immunomodulatory, immunosuppressive, and regenerative potentials, multipotent mesenchymal stem cells (MSCs) have received extensive scrutiny as an efficient tool for cell-based therapy of inflammatory, immune-mediated, and degenerative illnesses. Mesenchymal stem cells (MSCs) have been the subject of numerous preclinical and clinical research that looked into their therapeutic potential. This potential is primarily supported by MSCs' immunosuppressive characteristics. Even while there is still much to learn about the therapeutic characteristics of MSC transplantation, mounting evidence suggests that T and B cells undergo changes after MSC infusion, most notably the induction of regulatory T (Tregs) and B (Bregs) cells. Tregs and Bregs have been shown to exhibit immunosuppressive properties, and these cells are being considered as potential novel targets for the therapy of inflammatory disorders.

Spoilt for choice: different immunosuppressive potential of anaplastic lymphoma kinase inhibitors for non small cell lung cancer.

Several anaplastic lymphoma kinase (ALK)-inhibitors (ALKi) have been approved for the treatment of ALK-translocated advanced or metastatic Non Small Cell Lung Cancer (NSCLC), amongst crizotinib and alectinib. This forces physicians to choose the most suitable compound for each individual patient on the basis of the tumor´s genetic profile, but also in regard to toxicities and potential co-treatments. Moreover, targeted therapies might be combined with or followed by immunotherapy, which underlines the importance to gain detailed knowledge about potential immunomodulatory effects of these inhibitors. We here aimed to 1.) determine whether ALKi display an immunosuppressive effect on human dendritic cells (DCs) as important mediators of antigen-specific immunity and to 2.) dissect whether this immunosuppression differs among ALKi. We investigated the effect of alectinib and crizotinib on human monocyte-derived DCs (moDC) as most powerful antigen-presenting cells. We performed immunophenotyping by flow cytometry, migration, antigen uptake and cytokine assays. Crizotinib-treated DCs showed reduced activation markers, such as CD83, decreased chemokine-guided migration, lower antigen uptake and produced inferior levels of pro-inflammatory cytokines, especially Interleukin-12. In contrast, the immunosuppressive potential of alectinib was significantly less pronounced. This indicates that crizotinib might profoundly dampen anti-tumor immunity, while alectinib had no unfavourable immunosuppressive effects. Our results implicate that current ALKi differ in their capacity to suppress the activation, migration and cytokine production of DCs as essential mediators of T cell immunity. We show that crizotinib, but not alectinib, had immunosuppressive effects on DCs phenotype and reduced DC function, thereby potentially impairing anti-tumor immunity.

The anti-CD40L monoclonal antibody AT-1501 promotes islet and kidney allograft survival and function in nonhuman primates.

Prior studies of anti-CD40 ligand (CD40L)-based immunosuppression demonstrated effective prevention of islet and kidney allograft rejection in nonhuman primate models; however, clinical development was halted because of thromboembolic complications. An anti-CD40L-specific monoclonal antibody, AT-1501 (Tegoprubart), was engineered to minimize risk of thromboembolic complications by reducing binding to Fcγ receptors expressed on platelets while preserving binding to CD40L. AT-1501 was tested in both a cynomolgus macaque model of intrahepatic isletallotransplantation and a rhesus macaque model of kidney allotransplantation. AT-1501 monotherapy led to long-term graft survival in both islet and kidney transplant models, confirming its immunosuppressive potential. Furthermore, AT-1501-based regimens after islet transplant resulted in higher C-peptide, greater appetite leading to weight gain, and reduced occurrence of cytomegalovirus reactivation compared with conventional immunosuppression. These data support AT-1501 as a safe and effective agent to promote both islet and kidney allograft survival and function in nonhuman primate models, warranting further testing in clinical trials.

A review on mesenchymal stem cell-based therapies for autoimmune disorders

Mesenchymal stem cells (MSCs) or adult multipotent progenitor cells with the ability to self- renew and differentiate, are extracted from a variety of tissues, including bone marrow, adipose tissue, umbilical cord blood, Wharton’s jelly, tooth pulp, menstrual blood, and others. Since they are multipotent, cultured MSCs can differentiate into the adipogenic, chondrogenic, and osteogenic lineages after being isolated. Due to their immunomodulatory, immunosuppressive, and regenerative potentials, multipotent mesenchymal stem cells (MSCs) have received extensive scrutiny as an efficient tool for cell-based therapy of inflammatory, immune- mediated, and degenerative illnesses. The clinical applications and therapeutic potential of this cell type, the therapeutic mechanisms of MSCs, techniques to increase their therapeutic potentials, such as manipulation and preconditioning, and potential/unexpected risks that should be taken into account as a preliminary step before they are put to clinical use. In large part, due to their distinct immunomodulatory capabilities, MSCs have been touted as an ideal choice for the treatment of immune-related illnesses throughout the past few decades. In this review study we are mainly focusing on the MSC based treatments currently being developed for autoimmune diseases, type 1 diabetes and rheumatoid arthritis.

Case Report of Cellgram® Autologous Mesenchymal Stem Cell Treatment for Relapsing-Remitting Multiple Sclerosis

Multiple sclerosis is an autoimmune disease of the central nervous system that is increasing worldwide but difficult to diagnose and treat. Previous studies have revealed that the autologous Mesenchymal Stem Cells (MSC) for MS may serve as a possible effective tool for cell-based therapy of inflammatory, immune-mediated, and degenerative diseases due to their immunomodulatory, immunosuppressive, and regenerative potentials. This case report presents a patient diagnosed with Relapsing-Remitting Multiple Sclerosis (RRMS) who was treated with an autologous mesenchymal stem cell drug (Cellgram®). We administered two doses of Cellgram® to a 54-year-old Southwest Asian male with a 28-year history of RRMS. Changes were also observed in manual muscle strength test, range of motion, and lower extremity stiffness, but the biggest change was in functional performance. Before treatment, the patient was unable to stand without assistance even with an orthosis, but was able to stand up from a wheelchair using a walker on the 24th day after the first injection, and was able to stand up from the wheelchair without assistance on the 26th day. Thirty days after the first injection, and 3 days after the second injection, he was able to walk a few steps back and forth using a walker. Five months after the first injection, he was able to climb six steps. In conclusion, this case report illustrates that MSC therapy might serve as a potential therapeutic option for RRMS as it may be a safe and effective treatment for MS patients.

Extracellular vesicles derived from umbilical cord mesenchymal stromal cells show enhanced anti-inflammatory properties via upregulation of miRNAs after pro-inflammatory priming

Autoimmune conditions, such as rheumatoid arthritis, are characterised by a loss of immune tolerance, whereby the immune cells attack self-antigens causing pain and inflammation. These conditions can be brought into remission using pharmaceutical treatments, but often have adverse side effects and some patients do not respond favourably to them. Human umbilical cord mesenchymal stromal cells (UCMSCs) present a promising alternative therapeutic due to their innate anti-inflammatory properties which can be strengthened using pro-inflammatory conditions. Their therapeutic mechanism of action has been attributed to paracrine signalling, by which nanosized acellular particles called ‘extracellular vesicles’ (EVs) are one of the essential components. Therefore, this research analysed the anti-inflammatory properties of UCMSC-EVs ‘primed’ with pro-inflammatory cytokines and at baseline with no inflammatory cytokines (control). Both control and primed EVs were co-cultured with un-pooled peripheral blood mononuclear cells (PBMCs; n = 6) from healthy donors. Neither control nor primed EVs exerted a pro-inflammatory effect on PBMCs. Instead, the primed EVs showed the immunosuppressive potential by increasing the expression of the anti-inflammatory protein FoxP3 in PBMCs. This may be attributed to the upregulated miRNAs identified in primed EVs in comparison to control EVs (miR-139-5p, miR-140-5p, miR-214-5p). These findings aid in understanding how UCMSC-EVs mediate immunosuppression and support their potential use in treating autoimmune conditions.Graphical

Insights into the phylogenetic diversity, biological activities, and biosynthetic potential of mangrove rhizosphere Actinobacteria from Hainan Island.

Mangrove rhizosphere soils host diverse Actinobacteria tolerant to numerous stresses and are inevitably capable of exhibiting excellent biological activity by producing impressive numbers of bioactive natural products, including those with potential medicinal applications. In this study, we applied an integrated strategy of combining phylogenetic diversity, biological activities, and biosynthetic gene clusters (BGCs) screening approach to investigate the biotechnological importance of Actinobacteria isolated from mangrove rhizosphere soils from Hainan Island. The actinobacterial isolates were identifified using a combination of colony morphological characteristics and 16S rRNA gene sequence analysis. Based on the results of PCR-detected BGCs screening, type I and II polyketide synthase (PKS) and non-ribosomal synthetase (NRPS) genes were detected. Crude extracts of 87 representative isolates were subjected to antimicrobial evaluation by determining the minimum inhibitory concentration of each strain against six indicator microorganisms, anticancer activities were determined on human cancer cell lines HepG2, HeLa, and HCT-116 using an MTT colorimetric assay, and immunosuppressive activities against the proliferation of Con A-induced T murine splenic lymphocytes in vitro. A total of 287 actinobacterial isolates affiliated to 10 genera in eight families of six orders were isolated from five different mangrove rhizosphere soil samples, specififically, Streptomyces (68.29%) and Micromonospora (16.03%), of which 87 representative strains were selected for phylogenetic analysis. The crude extracts of 39 isolates (44.83%) showed antimicrobial activity against at least one of the six tested indicator pathogens, especially ethyl acetate extracts of A-30 (Streptomyces parvulus), which could inhibit the growth of six microbes with MIC values reaching 7.8 μg/mL against Staphylococcus aureus and its resistant strain, compared to the clinical antibiotic ciproflfloxacin. Furthermore, 79 crude extracts (90.80%) and 48 (55.17%) of the isolates displayed anticancer and immunosuppressive activities, respectively. Besides, four rare strains exhibited potent immunosuppressive activity against the proliferation of Con A-induced T murine splenic lymphocyte in vitro with an inhibition rate over 60% at 10 μg/mL. Type I and II polyketide synthase (PKS) and non-ribosomal synthetase (NRPS) genes were detected in 49.43, 66.67, and 88.51% of the 87 Actinobacteria, respectively. Signifificantly, these strains (26 isolates, 29.89%) harbored PKS I, PKS II, and NRPS genes in their genomes. Nevertheless, their bioactivity is independent of BGCs in this study. Our findings highlighted the antimicrobial, immunosuppressive, and anticancer potential of mangrove rhizosphere Actinobacteria from Hainan Island and the biosynthetic prospects of exploiting the corresponding bioactive natural product.

Abstract 527: Targeting citric acid cycle anaplerosis reverses the immunosuppressive phenotype of CD11b+Gr1+ myeloid cells in ovarian cancer

Abstract Immunosuppressive myeloid cells (CD11b+Gr1+) are a major constituent of the epithelial ovarian cancer (EOC) microenvironment that confer immunosuppression and promote tumor growth. We recently showed that the EOC microenvironment can induce metabolic reprogramming inCD11b+Gr1+ cells by increasing oxidative phosphorylation via TCA cycle, resulting in increased immunosuppressive ability. Increased TCA cycle activity was due to glutamine anaplerosis, which was facilitated by the upregulation of DLST (dihydrolipoamide succinyl transferase), the E2transferase subunit of α-KGDC (alpha-ketoglutarate dehydrogenase complex). We selected CPI-613 (Devimistat), an orphan metabolic drug, being actively tested in clinical trials to target the a-KGDC complex. We utilized the syngeneic ID8p53-/− model, a high grade serous ovarian cancer, to determine if CPI-613 may regulate CD11b+Gr1+ cell metabolism and immunosuppressive function and restore an antitumor immune response that inhibits EOC. One week after inducing tumors, mice were treated with CPI-613 (2.5mg/kg body weight) twice a week by IP injections or with vehicle (corn oil, control). CPI-613 treated mice showed significantly improved overall survival (median survival 75 days versus 48 days in control), decreased tumor progression and burden.CPI-613 decreased the number of CD11b+Gr1+ myeloid cells in ascites, and more importantly, reduced the intracellular immunosuppressive markers arginase 1 and IL-1β, indicating that the immunosuppressive potential was diminished, which was also validated by reversal of T cell suppression by CPI-613. The alleviation of immunosuppression was complemented by remarkable increase in CD8+ T effector cells. Further, combination of CPI-613 with anti-PD1(100ug/mice, every 5th day for 4 weeks) significantly improved survival and potentiated the CD8+mediated anti-tumor response. CPI-613 inhibited expression of DLST and immunosuppressive markers in the CD11b+Gr1+ myeloid cells, accompanied by decreased oxidative phosphorylation and decreased glutamine anaplerosis. Interestingly CPI-613 treatment also decreased the tumor associated macrophages, increased the M1 marker CD38 and decreased M2 marker EGR2, which reflected in increased M1/M2 macrophage ratio. Increased glutamine demand and addiction have been shown in variety of cancers, including EOC. We found that DLST expression corelates with worse progression free survival in the ovarian cancer TCGA dataset, implying that DLST is important in EOC cells. As a result, DLST targeting of aberrant glutamine metabolism will have the dual benefit of reducing CD11b+Gr1+ cell-mediated immunosuppression while also directly inhibiting tumor growth. Thus CPI-613 represents an attractive drug to target glutamine addiction and reduce immunosuppressive environment plaguing ovarian cancer. Citation Format: Mary Priyanka Udumula, Harshit Singh, Faraz Rashid, Miriana Hijaz, Radhika Gogoi, Philip Philip, Adnan Munkarah, Shailendra Giri, Ramandeep Rattan. Targeting citric acid cycle anaplerosis reverses the immunosuppressive phenotype of CD11b+Gr1+ myeloid cells in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 527.

DZIP1 expressed in fibroblasts and tumor cells may affect immunosuppression and metastatic potential in gastric cancer.

The tumor microenvironment (TME) contains complex components, of which the most well-known one is the tumor-associated fibroblast (CAF) that participates in the development and progression of tumors. A high abundance of CAFs implies that tumor stroma is also abundant and often predicts a poor prognosis, especially in terms of immunotherapeutic resistance. In this study, DAZ interacting zinc finger protein 1 (DZIP1) was identified to be upregulated in CAFs and malignant epithelial cells based on single-cell sequencing. Furthermore, results from The Cancer Genome Atlas database showed that this gene was highly positively associated with the mesenchymal phenotype in gastric cancer (GC). In addition, molecular experiments verified that DZIP1 directly promoted the proliferation of CAFs and enhanced the epithelial-mesenchymal transition (EMT) of GC cells to drive angiogenesis. Also, the upregulated DZIP1 in GC cells was found to directly promote invasion and metastasis. Finally, multiplex immunofluorescence and immunohistochemistry showed that DZIP1 was correlated with the immunosuppressive microenvironment of GC and resulted in a poor response to immunotherapy. Overall, our findings suggest that DZIP1 is expressed in both tumor parenchyma and mesenchyme and that it is involved in shaping the immunosuppressive microenvironment and inducing EMT by participating in tumor-stromal signaling crosstalk.

Mesenchymal stem cells-derived secretome and extracellular vesicles: perspective and challenges in cancer therapy and clinical applications.

Stem cell-based therapies have been foreshowed as a promising therapeutic approach for the treatment of several diseases. However, in the cancer context, results obtained from clinical studies were found to be quite limited. Deeply implicated in inflammatory cues, Mesenchymal, Neural, and Embryonic Stem Cells have mainly been used in clinical trials as a vehicle to deliver and stimulate signals in tumors niche. Although these stem cells have shown some therapeutical promises, they still face several challenges, including their isolation, immunosuppression potential, and tumorigenicity. In addition, regulatory and ethical concerns limit their use in several countries. Mesenchymal stem cells (MSC) have emerged as a gold standard adult stem cell medicine tool due to their distinctive characteristics, such as self-renewal and potency to differentiate into numerous cell types with lower ethical restrictions. Secreted extracellular vesicles (EVs), secretomes, and exosomes play a crucial role in mediating cell-to-cell communication to maintain physiological homeostasis and influence pathogenesis. Due to their low immunogenicity, biodegradability, low toxicity, and ability to transfer bioactive cargoes across biological barriers, EVs and exosomes were considered an alternative to stem cell therapy through their immunological features. MSCs-derived EVs, exosomes, and secretomes showed regenerative, anti-inflammatory, and immunomodulation properties while treating human diseases. In this review, we provide an overview of the paradigm of MSCs derived exosomes, secretome, and EVs cell-free-based therapies, we will focus on MSCs-derived components in anti-cancer treatment with decreased risk of immunogenicity and toxicity. Astute exploration of MSCs may lead to a new opportunity for efficient therapy for patients with cancer.

Maitake α-glucan promotes differentiation of monocytic myeloid-derived suppressor cells into M1 macrophages

AimsMyeloid-derived suppressor cells (MDSCs) are major components of the tumor microenvironment and systemically accumulate in tumor-bearing hosts and patients with cancer, facilitating cancer progression. Maitake macromolecular α-glucan YM-2A, isolated from Grifola frondosa, inhibits tumor growth by enhancing immune responses. The present study investigated the effects of YM-2A on the immunosuppressive potential of MDSCs. Main methodsYM-2A was orally administered to CT26 tumor-bearing mice, and the number of immune cells in the spleen and tumor was measured. Splenic MDSCs isolated from the CT26 tumor-bearing mice were treated with YM-2A and co-cultured with T cells to measure their inhibitory effect on T cell proliferation. For adoptive transfer of monocytic MDSCs (M-MDSCs), YM-2A-treated M-MDSCs mixed with CT26 cells were implanted subcutaneously in the mice to measure the tumor growth rate. Key findingsYM-2A selectively reduced the accumulation of M-MDSCs but not that of polymorphonuclear MDSCs (PMN-MDSCs) in CT26 tumor-bearing mice. In tumor tissues, YM-2A treatment induced the polarity of immunostimulatory M1-phenotype; furthermore, it increased the infiltration of dendritic, natural killer, and CD4+ and CD8+ T cells. YM-2A treatment of purified M-MDSCs from CT-26 tumor-bearing mice induced dectin-1-dependent differentiation into M1 macrophages. YM-2A-treated M-MDSCs lost their inhibitory activity against proliferation and activation of CD8+ T cells. Furthermore, adoptive transfer of M-MDSCs treated with YM-2A inhibited CT26 tumor growth. SignificanceYM-2A promotes the differentiation of M-MDSCs into immunostimulatory M1 macrophages, thereby enhancing the efficacy of cancer immunotherapy.

Updates in Prevention of Surgical Site Infection: Comment.

Long et al.1 provided a well-written and accessible review of new ideas in the field of surgical site infection prevention. Within their discussion of the patient’s microbiome, the authors touch on the potential for interactions between the patient microbiome and anesthetic agents administered perioperatively. Although they accurately identify the immunosuppressive potential of volatile anesthetics and intravenous opioids, we think that it is important to note that there exist other agents capable of producing and maintaining general anesthesia. Medications like ketamine and propofol are immunomodulatory in different ways, and thus their use may also impact the development of surgical site infections.Long et al.1 cite two mouse model articles where exposure to volatile anesthetics was associated with a decrease in intestinal microbiome diversity.2,3 In contrast, Guo et al.,4 using a rat model, looked at the effect of a continuous infusion of propofol during a 3-h period on the intestinal microbiome and found little change in the diversity of the intestinal microbiome after exposure to propofol. Similarly, Gerb et al.5 looked at the effects on the intestinal microbiome of mice after 10 daily exposures to a bolus dose of ketamine that rendered the mice unconscious for approximately 15 to 30 min per ketamine exposure and also found little change in the diversity of the intestinal microbiome.No definitive evidence exists to recommend one type of anesthetic over another. Given the minimal impact on the intestinal microbiome, it might be tempting to conclude that replacing volatile anesthetics with agents such as propofol and ketamine might decrease the incidence of surgical site infection. But there is also evidence to the contrary. For example, Visvabharathy et al.6 looked at susceptibility to infection due to exogenous bacteremia using Listeria and Staphylococcus aureus in mice receiving intravenous propofol compared to mice receiving intravenous ketamine with xylazine and found that propofol increased susceptibility to infection. In a research letter, Liu et al.7 looked at the intestinal microbiome in 21 patients undergoing nephrectomy with propofol alone compared to sevoflurane alone compared to propofol and sevoflurane combined and found that the mixed anesthetic7 was associated with the fewest perturbations.Clearly it remains premature to advocate for a total intravenous technique in the absence of more clinically robust data. Further research in animal models and in humans is needed to try and elucidate not only if there is an optimal anesthetic agent for prevention of surgical site infection, but also what the combined effects of multiple anesthetics, as routinely administered when patients present for surgery, have on the patient’s susceptibility to infection after surgery.Surgical site infections are a multidisciplinary problem. Once more data are available, it may turn out that the effects of anesthetic agents are small and of minor importance in patients with normal immune systems. But the selection of anesthetic agents is one aspect we have almost complete control over; we should be making every effort to maximize the ability of the patient’s immune system to combat infection.The authors declare no competing interests.

Regulatory mucosa-associated invariant T cells controlled by β1 adrenergic receptor signaling contribute to hepatocellular carcinoma progression.

The innate-like mucosa-associated invariant T (MAIT) cells are enriched in human liver and have been linked to human HCC. However, their contributions to the progression of HCC are controversial due to the heterogeneity of MAIT cells, and new MAIT cell subsets remain to be explored. Combining single cell RNA sequencing (scRNA-seq) and flow cytometry analysis, we performed phenotypic and functional studies and found that FOXP3 + CXCR3 + MAIT cells in HCC patients were regulatory MAIT cells (MAITregs) with high immunosuppressive potential. These MAITregs were induced under Treg-inducing condition and predominantly from FOXP3 - CXCR3 + MAIT cells, which displayed mild Treg-related features and represented a pre-MAITreg reservoir. In addition, the induction and function of MAITregs were promoted by β1 adrenergic receptor signaling in pre-MAITregs and MAITregs, respectively. In HCC patients, high proportion of the intratumoral MAITregs inhibited antitumor immune responses and was associated with poor clinical outcomes. Together, we reveal an immunosuppressive subset of MAIT cells in HCC patients that contributes to HCC progression, and propose a control through neuroimmune crosstalk.

Prognostic significance of ımmunhistochemical axl expression in pancreas ductal adenocarcinomas.

Pancreas Ductal Adenocarcinomas (PDACs) are among the leading causes of cancer-related death. Tyrosine kinase receptors (TKRs) are responsible for cell plasticity, chemoresistance, immunosuppression and metastasis potential. Axl is a receptor of the TKR family, and it has come to the fore in cancer treatment in the last decade. This study aimed to investigate the relationship of immunohistochemical Axl expression with histological features and its prognostic importance in PDACs. Fifty-three patients who were operated on for PDAC between 2006-2017 were evaluated retrospectively. Features of tumors; size, lymphovascular invasion (LVI), perineural invasion (PNI), resection margin (RM), lymph node metastasis (LNM), differentiation, tumor-infiltrating lymphocyte, stage and overall survival were recorded. Immunohistochemically, membranous and or cytoplasmic staining was considered positive for Axl. Statistically, Pearson Chi-Square, Cox regression and Kaplan Mayer tests were used in the SPSS 21.0 program. Axl was positive in 28 patients (52.8%). Axl positivity was found to be associated with the presence of LVI (P = 0.009) and LNM (P = 0.002) and was an independent prognostic factor in short survival (P = 0.006). It was found that increased expression of Axl, which is known to increase EMT-mediated metastasis in carcinogenesis, may be an indicator of local spread and poor prognosis in PDAC patients. In this respect, it can be promising as a targeted molecule in PDAC patient's individualized treatments.

The Immunosuppressive Potential of Cholesterol Sulfate Through T Cell Microvilli Disruption.

Cholesterol (CL) is required for various biomolecular production processes, including those of cell membrane components. Therefore, to meet these needs, CL is converted into various derivatives. Among these derivatives is cholesterol sulfate (CS), a naturally produced CL derivative by the sulfotransferase family 2B1 (SULT2B1), which is widely present in human plasma. CS is involved in cell membrane stabilization, blood clotting, keratinocyte differentiation, and TCR nanocluster deformation. This study shows that treatment of T cells with CS resulted in the decreased surface expression of some surface T-cell proteins and reduced IL-2 release. Furthermore, T cells treated with CS significantly reduced lipid raft contents and membrane CLs. Surprisingly, using the electron microscope, we also observed that CS led to the disruption of T-cell microvilli, releasing small microvilli particles containing TCRs and other microvillar proteins. However, in vivo, T cells with CS showed aberrant migration to high endothelial venules and limited infiltrating splenic T-cell zones compared with the untreated T cells. Additionally, we observed significant alleviation of atopic dermatitis in mice injected with CS in the animal model. Based on these results, we conclude that CS is an immunosuppressive natural lipid that impairs TCR signaling by disrupting microvillar function in T cells, suggesting its usefulness as a therapeutic agent for alleviating T-cell-mediated hypersensitivity and a potential target for treating autoimmune diseases.