Thy-1: More than a Mouse Pan-T Cell Marker

Mining human clinical waste as a rich source of stem cells for neural regeneration

Neural diseases are challenging to treat and are regarded as one of the major causes of disability and morbidity in the world. Stem cells can provide a solution, by offering a mechanism to replace damaged circuitry. However, obtaining sufficient cell sources for neural regeneration remains a significant challenge. In recent years, waste-derived stem(-like) cells (WDS-lCs) extracted from both prenatal and adult clinical waste tissues/products, have gained increasing attention for application in neural tissue repair and remodeling. This often-overlooked pool of cells possesses favorable characteristics; including self-renewal, neural differentiation, secretion of neurogenic factors, cost-effectiveness, and low ethical concerns. Here, we offer a perspective regarding the biological properties, extraction protocols, and preclinical and clinical treatments where prenatal and adult WDS-lCs have been utilized for cell replacement therapy in neural applications, and the challenges involved in optimizing these approaches toward patient led therapies.

Characterization of CD90/Thy-1 as a crucial molecular signature for myogenic differentiation in human urine-derived cells through single-cell RNA sequencing

Human urine-derived cells (UDCs) are primary cultured cells originating from the upper urinary tract and are known to be multipotent. We previously developed MYOD1-transduced UDCs (MYOD1-UDCs) as a model recapitulating the pathogenesis of Duchenne muscular dystrophy (DMD) caused by a lack of dystrophin. MYOD1-UDCs also allow evaluation of the efficacy of exon skipping with antisense oligonucleotides. However, despite the introduction of MYOD1, some MYOD1-UDCs failed to form myotubes, possibly because of heterogeneity among UDCs. Here, we carried out single-cell RNA-sequencing analyses and revealed that CD90/Thy-1 was highly expressed in a limited subpopulation of UDCs with high myogenic potency. Furthermore, CD90-positive MYOD1-UDCs, but not CD90-negative cells, could form myotubes expressing high levels of myosin heavy chain and dystrophin. Notably, overexpression of CD90 in CD90-negative MYOD1-UDCs did not enhance myogenic differentiation, whereas CD90 suppression in CD90-positive UDCs led to decreased myotube formation and decreased myosin heavy chain expression. CD90 may thus contribute to the fusion of single-nucleated MYOD1-UDCs into myotubes but is not crucial for promoting the expression of late muscle regulatory factors. Finally, we confirmed that CD90-positive MYOD1-UDCs derived from patients with DMD were a valuable tool for obtaining a highly reproducible and stable evaluation of exon skipping using antisense oligonucleotide.

The expression profile and tumorigenic mechanisms of CD97 (ADGRE5) in glioblastoma render it a targetable vulnerability

Glioblastoma (GBM) is the most common and aggressive primary brain malignancy. Adhesion G protein-coupled receptors (aGPCRs) have attracted interest for their potential as treatment targets. Here, we show that CD97 (ADGRE5) is the most promising aGPCR target in GBM, by virtue of its de novo expression compared to healthy brain tissue. CD97 knockdown or knockout significantly reduces the tumor initiation capacity of patient-derived GBM cultures (PDGCs) in vitro and in vivo. We find that CD97 promotes glycolytic metabolism via the mitogen-activated protein kinase (MAPK) pathway, which depends on phosphorylation of its C terminus and recruitment of β-arrestin. We also demonstrate that THY1/CD90 is a likely CD97 ligand in GBM. Lastly, we show that an anti-CD97 antibody-drug conjugate selectively kills tumor cells in vitro. Our studies identify CD97 as a regulator of tumor metabolism, elucidate mechanisms of receptor activation and signaling, and provide strong scientific rationale for developing biologics to target it therapeutically in GBM.

Cancer Stem Cell Markers-Clinical Relevance and Prognostic Value in High-Grade Serous Ovarian Cancer (HGSOC) Based on The Cancer Genome Atlas Analysis

Cancer stem cells (CSCs) may contribute to an increased risk of recurrence in ovarian cancer (OC). Further research is needed to identify associations between CSC markers and OC patients' clinical outcomes with greater certainty. If they prove to be correct, in the future, the CSC markers can be used to help predict survival and indicate new therapeutic targets. This study aimed to determine the CSC markers at mRNA and protein levels and their association with clinical presentation, outcome, and risk of recurrence in HGSOC (High-Grade Serous Ovarian Cancer). TCGA (The Cancer Genome Atlas) database with 558 ovarian cancer tumor samples was used for the evaluation of 13 CSC markers (ALDH1A1, CD44, EPCAM, KIT, LGR5, NES, NOTCH3, POU5F1, PROM1, PTTG1, ROR1, SOX9, and THY1). Data on mRNA and protein levels assessed by microarray and mass spectrometry were retrieved from TCGA. Models to predict chemotherapy response and survival were built using multiple variables, including epidemiological data, expression levels, and machine learning methodology. ALDH1A1 and LGR5 mRNA expressions indicated a higher platinum sensitivity (p = 3.50 × 10-3; p = 0.01, respectively). POU5F1 mRNA expression marked platinum-resistant tumors (p = 9.43 × 10-3). CD44 and EPCAM mRNA expression correlated with longer overall survival (OS) (p = 0.043; p = 0.039, respectively). THY1 mRNA and protein levels were associated with worse OS (p = 0.019; p = 0.015, respectively). Disease-free survival (DFS) was positively affected by EPCAM (p = 0.004), LGR5 (p = 0.018), and CD44 (p = 0.012). In the multivariate model based on CSC marker expression, the high-risk group had 9.1 months longer median overall survival than the low-risk group (p < 0.001). ALDH1A1, CD44, EPCAM, LGR5, POU5F1, and THY1 levels in OC may be used as prognostic factors for the primary outcome and help predict the treatment response.

Coupling of protein condensates to ordered lipid domains determines functional membrane organization

During T cell activation, the transmembrane adaptor protein LAT (linker for activation of T cells) forms biomolecular condensates with Grb2 and Sos1, facilitating signaling. LAT has also been associated with cholesterol-rich condensed lipid domains; However, the potential coupling between protein condensation and lipid phase separation and its role in organizing T cell signaling were unknown. Here, we report that LAT/Grb2/Sos1 condensates reconstituted on model membranes can induce and template lipid domains, indicating strong coupling between lipid- and protein-based phase separation. Correspondingly, activation of T cells induces cytoplasmic protein condensates that associate with and stabilize raft-like membrane domains. Inversely, lipid domains nucleate and stabilize LAT protein condensates in both reconstituted and living systems. This coupling of lipid and protein assembly is functionally important, as uncoupling of lipid domains from cytoplasmic protein condensates abrogates T cell activation. Thus, thermodynamic coupling between protein condensates and ordered lipid domains regulates the functional organization of living membranes.

The Role of Mesothelin in Activation of Portal Fibroblasts in Cholestatic Liver Injury

Fibrosis is a common consequence of abnormal wound healing, which is characterized by infiltration of myofibroblasts and formation of fibrous scar. In liver fibrosis, activated Hepatic Stellate Cells (aHSCs) and activated Portal Fibroblasts (aPFs) are the major contributors to the origin of hepatic myofibroblasts. aPFs are significantly involved in the pathogenesis of cholestatic fibrosis, suggesting that aPFs may be a primary target for anti-fibrotic therapy in cholestatic injury. aPFs are distinguishable from aHSCs by specific markers including mesothelin (Msln), Mucin 16 (Muc16), and Thymus cell antigen 1 (Thy1, CD90) as well as fibulin 2, elastin, Gremlin 1, ecto-ATPase nucleoside triphosphate diphosphohydrolase 2. Msln plays a critical role in activation of PFs, via formation of Msln-Muc16-Thy1 complex that regulates TGFβ1/TGFβRI-mediated fibrogenic signaling. The opposing pro- and anti-fibrogenic effects of Msln and Thy1 are key components of the TGFβ1-induced activation pathway in aPFs. In addition, aPFs and activated lung and kidney fibroblasts share similarities across different organs with expression of common markers and activation cascade including Msln-Thy1 interaction. Here, we summarize the potential function of Msln in activation of PFs and development of cholestatic fibrosis, offering a novel perspective for anti-fibrotic therapy targeting Msln.

Thy-1-Integrin Interactions in cis and Trans Mediate Distinctive Signaling

Thy-1 is a cell surface glycosylphosphatidylinositol (GPI)-anchored glycoprotein that bears a broad mosaic of biological roles across various cell types. Thy-1 displays strong physiological and pathological implications in development, cancer, immunity, and tissue fibrosis. Quite uniquely, Thy-1 is capable of mediating integrin-related signaling through direct trans- and cis-interaction with integrins. Both interaction types have shown distinctive roles, even when interacting with the same type of integrin, where binding in trans or in cis often yields divergent signaling events. In this review, we will revisit recent progress and discoveries of Thy-1–integrin interactions in trans and in cis, highlight their pathophysiological consequences and explore other potential binding partners of Thy-1 within the integrin regulation/signaling paradigm.

Association of CD90 Expression by CD14+ Dendritic-Shaped Cells in Rheumatoid Arthritis Synovial Tissue With Chronic Inflammation

Objective

CD14⁺ dendritic‐shaped cells show a dendritic morphology under the electron microscopy and engage in a pseudoemperipolesis phenomenon with lymphocytes. CD90 has been used as a marker of a major subset of fibroblast‐like synoviocytes in rheumatoid arthritis (RA). In this study, we investigated the significance of CD90 expression in CD14⁺ dendritic‐shaped cells and its correlation with RA chronic inflammation.

Methods

Double immunofluorescence staining for CD14 and CD90 was performed in the collected tissues, including 12 active RA synovial tissues. The localization of CD14⁺CD90⁺ cells, the percentages of CD14⁺CD90⁺ cells and vascular areas, the degree of synovitis, and clinical data were investigated. Furthermore, CD14⁺CD90⁺ cells analyzed by flow cytometry (CD14^highCD90^{intermediate (int)} cells) were sorted from RA synovial cells, and we examined their potential to differentiate into dendritic cells.

Results

Double immunofluorescence staining showed that CD14⁺CD90⁺ cells were abundant in RA synovial tissues. The percentages of CD14⁺CD90⁺ cells and vascular areas correlated with some of the Krenn synovitis scores, but neither showed a strong correlation with RA disease activity parameters. Flow cytometry analysis indicated that CD14^highCD90^int cells were more abundant in both peripheral blood samples and synovial tissues in patients with active RA. CD14^highCD90^int cells were more likely to differentiate into dendritic cells in vitro.

Conclusion

CD14⁺ dendritic‐shaped cells expressed CD90 in the perivascular areas of RA synovial tissues. These findings suggest that CD14⁺CD90⁺ dendritic‐shaped cells migrate from the peripheral blood to the synovial tissue, the site of inflammation, and may contribute to the chronic inflammation of RA as dendritic progenitor cells.

Oncolytic Orf virus licenses NK cells via cDC1 to activate innate and adaptive antitumor mechanisms and extends survival in a murine model of late-stage ovarian cancer

BACKGROUND

Novel therapies are needed to improve outcomes for women diagnosed with ovarian cancer. Oncolytic viruses are multifunctional immunotherapeutic biologics that preferentially infect cancer cells and stimulate inflammation with the potential to generate antitumor immunity. Herein we describe Parapoxvirus ovis (Orf virus (OrfV)), an oncolytic poxvirus, as a viral immunotherapy for ovarian cancer.

METHODS

The immunotherapeutic potential of OrfV was tested in the ID8 orthotopic mouse model of end-stage epithelial ovarian carcinoma. Immune cell profiling, impact on secondary lesion development and survival were evaluated in OrfV-treated mice as well as in Batf3 knockout, mice depleted of specific immune cell subsets and in mice where the primary tumor was removed. Finally, we interrogated gene expression datasets from primary human ovarian tumors from the International Cancer Genome Consortium database to determine whether the interplay we observed between natural killer (NK) cells, classical type 1 dendritic cells (cDC1s) and T cells exists and influences outcomes in human ovarian cancer.

RESULTS

OrfV was an effective monotherapy in a murine model of advanced-stage epithelial ovarian cancer. OrfV intervention relied on NK cells, which when depleted abrogated antitumor CD8⁺ T-cell responses. OrfV therapy was shown to require cDC1s in experiments with BATF3 knockout mice, which do not have mature cDC1s. Furthermore, cDC1s governed antitumor NK and T-cell responses to mediate antitumor efficacy following OrfV. Primary tumor removal, a common treatment option in human patients, was effectively combined with OrfV for optimal therapeutic outcome. Analysis of human RNA sequencing datasets revealed that cDC1s correlate with NK cells in human ovarian cancer and that intratumoral NK cells correlate positively with survival.

CONCLUSIONS

The data herein support the translational potential of OrfV as an NK stimulating immunotherapeutic for the treatment of advanced-stage ovarian cancer.

cPLA2 blockade attenuates S100A7-mediated breast tumorigenicity by inhibiting the immunosuppressive tumor microenvironment

BACKGROUND

Molecular mechanisms underlying inflammation-associated breast tumor growth are poorly studied. S100A7, a pro-inflammatory molecule has been shown to enhance breast cancer growth and metastasis. However, the S100A7-mediated molecular mechanisms in enhancing tumor growth and metastasis are unclear.

METHODS

Human breast cancer tissue and plasma samples were used to analyze the expression of S100A7, cPLA2, and PGE2. S100A7-overexpressing or downregulated human metastatic breast cancer cells were used to evaluate the S100A7-mediated downstream signaling mechanisms. Bi-transgenic mS100a7a15 overexpression, TNBC C3 (1)/Tag transgenic, and humanized patient-derived xenograft mouse models and cPLA2 inhibitor (AACOCF3) were used to investigate the role of S100A7/cPLA2/PGE2 signaling in tumor growth and metastasis. Additionally, CODEX, a highly advanced multiplexed imaging was employed to delineate the effects of S100A7/cPLA2 inhibition on the recruitment of various immune cells.

RESULTS

In this study, we found that S100A7 and cPLA2 are highly expressed and correlate with decreased overall survival in breast cancer patients. Further mechanistic studies revealed that S100A7/RAGE signaling promotes the expression of cPLA2 to mediate its oncogenic effects. Pharmacological inhibition of cPLA2 suppressed S100A7-mediated tumor growth and metastasis in multiple pre-clinical models including transgenic and humanized patient-derived xenograft (PDX) mouse models. The attenuation of cPLA2 signaling reduced S100A7-mediated recruitment of immune-suppressive myeloid cells in the tumor microenvironment (TME). Interestingly, we discovered that the S100A7/cPLA2 axis enhances the immunosuppressive microenvironment by increasing prostaglandin E2 (PGE2). Furthermore, CO-Detection by indEXing (CODEX) imaging-based analyses revealed that cPLA2 inhibition increased the infiltration of activated and proliferating CD4⁺ and CD8⁺ T cells in the TME. In addition, CD163⁺ tumor associated-macrophages were positively associated with S100A7 and cPLA2 expression in malignant breast cancer patients.

CONCLUSIONS

Our study provides new mechanistic insights on the cross-talk between S100A7/cPLA2 in enhancing breast tumor growth and metastasis by generating an immunosuppressive TME that inhibits the infiltration of cytotoxic T cells. Furthermore, our studies indicate that S100A7/cPLA2 could be used as novel prognostic marker and cPLA2 inhibitors as promising drugs against S100A7-overexpressing aggressive breast cancer.

Thy-1 (CD90), Integrins and Syndecan 4 are Key Regulators of Skin Wound Healing

Acute skin wound healing is a multistage process consisting of a plethora of tightly regulated signaling events in specialized cells. The Thy-1 (CD90) glycoprotein interacts with integrins and the heparan sulfate proteoglycan syndecan 4, generating a trimolecular complex that triggers bi-directional signaling to regulate diverse aspects of the wound healing process. These proteins can act either as ligands or receptors, and they are critical for the successful progression of wound healing. The expression of Thy-1, integrins, and syndecan 4 is controlled during the healing process, and the lack of expression of any of these proteins results in delayed wound healing. Here, we review and discuss the roles and regulatory events along the stages of wound healing that support the relevance of Thy-1, integrins, and syndecan 4 as crucial regulators of skin wound healing.

The interplay of fibroblasts, the extracellular matrix, and inflammation in scar formation

Various forms of fibrosis, comprising tissue thickening and scarring, are involved in 40% of deaths across the world. Since the discovery of scarless functional healing in fetuses prior to a certain stage of development, scientists have attempted to replicate scarless wound healing in adults with little success. While the extracellular matrix (ECM), fibroblasts, and inflammatory mediators have been historically investigated as separate branches of biology, it has become increasingly necessary to consider them as parts of a complex and tightly regulated system that becomes dysregulated in fibrosis. With this new paradigm, revisiting fetal scarless wound healing provides a unique opportunity to better understand how this highly regulated system operates mechanistically. In the following review, we navigate the four stages of wound healing (hemostasis, inflammation, repair, and remodeling) against the backdrop of adult versus fetal wound healing, while also exploring the relationships between the ECM, effector cells, and signaling molecules. We conclude by singling out recent findings that offer promising leads to alter the dynamics between the ECM, fibroblasts, and inflammation to promote scarless healing. One factor that promises to be significant is fibroblast heterogeneity and how certain fibroblast subpopulations might be predisposed to scarless healing. Altogether, reconsidering fetal wound healing by examining the interplay of the various factors contributing to fibrosis provides new research directions that will hopefully help us better understand and address fibroproliferative diseases, such as idiopathic pulmonary fibrosis, liver cirrhosis, systemic sclerosis, progressive kidney disease, and cardiovascular fibrosis.

Modified BuShenYiQi formula alleviates experimental allergic asthma in mice by negative regulation of type 2 innate lymphoid cells and CD4+ type 9 helper T cells and the VIP-VPAC2 signalling pathway

CONTEXT

Modified BuShenYiQi formula (M-BYF) is derived from BuShenYiQi formula, used for the treatment of allergic asthma. The exact effect and mechanism of M-BYF on the improvement of asthma remain unclear.

OBJECTIVE

We investigated the mechanism underlying the therapeutic effect of M-BYF on allergic asthma.

MATERIALS AND METHODS

The asthma model was established in female BALB/c mice that were sensitized and challenged with ovalbumin (OVA). Mice in the treated groups were orally treated once a day with M-BYF (7, 14 and 28 g/kg/d) or dexamethasone before OVA challenge. Control and Model group received saline. Pathophysiological abnormalities and percentages of lung type 2 innate lymphoid cells (ILC2s) and Th9 cells were measured. Expression levels of type 2 cytokines and transcription factors required for these cells function and differentiation were analysed. Expression of vasoactive intestinal polypeptide (VIP)-VPAC2 signalling pathway-related proteins, and percentages of VIP expressing (VIP⁺) cells and VPAC2, CD90 co-expressing (VPAC2⁺CD90⁺) cells were detected.

RESULTS

M-BYF alleviated airway hyperresponsiveness, inflammation, mucus hypersecretion and collagen deposition in asthmatic mice. M-BYF down-regulated percentages of ILC2s and Th9 cells with lower expression of GATA3, PU.1 and IRF4, reduced IL-5, IL-13, IL-9 and VIP production. The decrease in the expression of VIP-VPAC2 signalling pathway and percentages of VIP⁺ cells, VPAC2⁺CD90⁺ cells were observed after M-BYF treatment. The LD₅₀ value of M-BYF was higher than 90 g/kg.

DISCUSSION AND CONCLUSIONS

M-BYF alleviated experimental asthma by negatively regulating ILC2s and Th9 cells and the VIP-VPAC2 signalling pathway. These findings provide the theoretical basis for future research of M-BYF in asthma patient population.

Activation status dictates the function of unlicensed natural killer cells in mice and humans

The activation status of NK cell subsets is affected by viral load and immune context.

Licensed NK cells dominate the antiviral response in mice after hematopoietic stem cell transplant.

Natural killer (NK) cells are involved in innate defense against viral infection and cancer. NK cells can be divided into subsets based on the ability of different receptors to bind to major histocompatibility (MHC) class 1 molecules, resulting in differential responses upon activation in a process called “licensing” or “arming.” NK cells expressing receptors that bind self-MHC are considered licensed due to an augmented effector lytic function capability compared with unlicensed subsets. However, we demonstrated that unlicensed NK subsets instead positively regulate the adaptive T-cell response during viral infections that are related to localization and cytokine production. In this study, the differential effects of the two types of NK subsets were contingent on the environment in viral infection and hematopoietic stem cell transplantation (HSCT) models. Infection of mice with high-dose (HD) murine cytomegalovirus (MCMC) led to a loss of licensing-associated differences, as compared with mice with low-dose (LD) infection: the unlicensed NK subset no longer localized in lymph nodes (LNs), but instead remained at the site of infection. Similarly, the patterns observed during HD infection paralleled the phenotypes of both human and mouse NK cells in an HSCT setting where NK cells exhibit an activated phenotype. However, in contrast to the effects of subset depletion in T-cell replete models, the licensed NK cell subsets still dominated antiviral responses after HSCT. Overall, our results highlight the intricate tuning of NK cells and how it affects overall immune responses with regard to licensing patterns and their dependency on the level of stimulation and activation status.

Fibroblast pathology in inflammatory joint disease

Rheumatoid arthritis is an immune-mediated inflammatory disease in which fibroblasts contribute to both joint damage and inflammation. Fibroblasts are a major cell constituent of the lining of the joint cavity called the synovial membrane. Under resting conditions, fibroblasts have an important role in maintaining joint homeostasis, producing extracellular matrix and joint lubricants. In contrast, during joint inflammation, fibroblasts contribute to disease pathology by producing pathogenic levels of inflammatory mediators that drive the recruitment and retention of inflammatory cells within the joint. Recent advances in single-cell profiling techniques have transformed our ability to examine fibroblast biology, leading to the identification of specific fibroblast subsets, defining a previously underappreciated heterogeneity of disease-associated fibroblast populations. These studies are challenging the previously held dogma that fibroblasts are homogeneous and are providing unique insights into their role in inflammatory joint pathology. In this review, we discuss the recent advances in our understanding of how fibroblast heterogeneity contributes to joint pathology in rheumatoid arthritis. Finally, we address how these insights could lead to the development of novel therapies that directly target selective populations of fibroblasts in the future.

Optimizing adipogenic transdifferentiation of bovine mesenchymal stem cells: a prominent role of ascorbic acid in FABP4 induction

Adipocyte differentiation of bovine adipose-derived stem cells (ASC) was induced by foetal bovine serum (FBS), biotin, pantothenic acid, insulin, rosiglitazone, dexamethasone and 3-isobutyl-1-methylxanthine, followed by incubation in different media to test the influence of ascorbic acid (AsA), bovine serum lipids (BSL), FBS, glucose and acetic acid on transdifferentiation into functional adipocytes. Moreover, different culture plate coatings (collagen-A, gelatin-A or poly-L-lysine) were tested. The differentiated ASC were subjected to Nile red staining, DAPI staining, immunocytochemistry and quantitative reverse transcription PCR (for NT5E, THY1, ENG, PDGFRα, FABP4, PPARγ, LPL, FAS, GLUT4). Nile red quantification showed a significant increase in the development of lipid droplets in treatments with AsA and BSL without FBS. The presence of BSL induced a prominent increase in FABP4 mRNA abundance and in FABP4 immunofluorescence signals in coincubation with AsA. The abundance of NT5E, ENG and THY1 mRNA decreased or tended to decrease in the absence of FBS, and ENG was additionally suppressed by AsA. DAPI fluorescence was higher in cells cultured in poly-L-lysine or gelatin-A coated wells. In additional experiments, the multi-lineage differentiation potential to osteoblasts was verified in medium containing ß-glycerophosphate, dexamethasone and 1,25-dihydroxyvitamin D₃ using alizarin red staining. In conclusion, bovine ASC are capable of multi-lineage differentiation. Poly-L-lysine or gelatin-A coating, the absence of FBS, and the presence of BSL and AsA favour optimal transdifferentiation into adipocytes. AsA supports transdifferentiation via a unique role in FABP4 induction, but this is not linearly related to the primarily BSL-driven lipid accumulation.

Abbreviations: AcA: acetic acid; AsA: ascorbic acid; ASC: adipose-derived stem cells; BSL: bovine serum lipids; DAPI: 4´,6-diamidino-2-phenylindole; DLK: delta like non-canonical notch ligand; DMEM: Dulbecco’s modified Eagle’s medium; DPBS: Dulbecco’s phosphate-buffered saline; ENG: endoglin; FABP: fatty acid binding protein; FAS: fatty acid synthase; GLUT4: glucose transporter type 4; IBMX: 3-isobutyl-1-methylxanthine; LPL: lipoprotein lipase; MSC: mesenchymal stem cells; α-MEM: α minimum essential medium; NT5E: ecto-5ʹ-nucleotidase; PDGFRα: platelet derived growth factor receptor α; PPARγ: peroxisome proliferator activated receptor γ; RPS19: ribosomal protein S19; SEM: standard error of the mean; THY1: Thy-1 cell surface antigen; TRT: treatment; TRT-Con: treatment negative control; YWHAZ: tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta

CD26 Identifies a Subpopulation of Fibroblasts that Produce the Majority of Collagen during Wound Healing in Human Skin

Fibroblasts produce collagens and other proteins that form the bulk of the extracellular matrix (ECM) in connective tissues. Emerging data point to functional heterogeneity of fibroblasts. However, the lack of subtype-specific markers hinders our understanding of the different roles of fibroblasts in ECM biology, wound healing, diseases, and aging. We have investigated the utility of the cell surface protein CD26 to identify functionally distinct fibroblast subpopulations in human skin. Using flow cytometry and immunohistology, we found that CD26, in combination with the cell surface glycoprotein CD90, identifies a distinct subpopulation of cells, which express relatively high levels of COL1A1, a hallmark of fibroblasts. Importantly, the population of CD26+ fibroblasts is selectively increased after wounding of human skin. These cells account for the majority of COL1A1 expression during the ECM remodeling phase of healing. The proportion of CD26+ fibroblasts in the skin of young and aged individuals is similar, indicating that the loss of collagen production during aging does not involve selective reduction of CD26+ fibroblasts. In culture, the majority of freshly isolated CD26- fibroblasts gain expression of CD26+. Taken together, these data provide a foundation for targeting CD26+ fibroblasts to modulate wound healing in human skin.

Chemokine Signatures of Pathogen-Specific T Cells I: Effector T Cells

The choreography of complex immune responses, including the priming, differentiation, and modulation of specific effector T cell populations generated in the immediate wake of an acute pathogen challenge, is in part controlled by chemokines, a large family of mostly secreted molecules involved in chemotaxis and other patho/physiological processes. T cells are both responsive to various chemokine cues and a relevant source for certain chemokines themselves; yet, the actual range, regulation, and role of effector T cell-derived chemokines remains incompletely understood. In this study, using different in vivo mouse models of viral and bacterial infection as well as protective vaccination, we have defined the entire spectrum of chemokines produced by pathogen-specific CD8⁺ and CD4⁺T effector cells and delineated several unique properties pertaining to the temporospatial organization of chemokine expression patterns, synthesis and secretion kinetics, and cooperative regulation. Collectively, our results position the "T cell chemokine response" as a notably prominent, largely invariant, yet distinctive force at the forefront of pathogen-specific effector T cell activities and establish novel practical and conceptual approaches that may serve as a foundation for future investigations into the role of T cell-produced chemokines in infectious and other diseases.

Loss of Thy-1 may reduce lung regeneration after pneumonectomy in mice

BACKGROUND

Lung regeneration plays an important role in lung repair after injury. It is reliant upon proliferation of multiple cell types in the lung, including endothelium, epithelium, and fibroblasts, as well as remodeling of the extracellular matrix.

METHODS

Lung regeneration following injury progresses via an initial infammatory response during which macrophages clear the tissue of cellular debris. This process continues through cellular proliferation when existing cells and progenitors act to repopulate cells lost during injury, followed by tissue maturation in which newly formed cells achieve a diferentiated phenotype.

RESULTS

Signaling pathways critical for lung regeneration include FGF, EGF, WNT, and NOTCH. In addition, HDACs, miRNAs, ELASTIN, and MMP14 have been shown to regulate lung regeneration. Partial pneumonectomy (PNX) has been used as a therapeutic and investigational tool for several decades. Following PNX the remaining lung increases in size to compensate for loss of volume and respiratory capacity.

CONCLUSIONS

Much has been learned about the triggers and mechanisms regulating pulmonary regeneration. However, the role of thymocyte differentiation antigen-1(thy-1) in post-PNX lung growth remains incompletely characterized. Thy-1 is a phosphatidylinositol glycoprotein with a relative molecular weight of 25000~37000 Da, which is expressed in almost all types of fibroblasts and regulates many biological functions. It not only supports the structure of fibroblasts, but also can balance cell proliferation, migration and regulate the synthesis of immune inflammatory mediators.

Comparative label-free mass spectrometric analysis of temporal changes in the skeletal muscle proteome after impact trauma in rats

Proteomics offers the opportunity to identify and quantify many proteins and to explore how they correlate and interact with each other in biological networks. This study aimed to characterize changes in the muscle proteome during the destruction, repair, and early-remodeling phases after impact trauma in male Wistar rats. Muscle tissue was collected from uninjured control rats and rats that were euthanized between 6 h and 14 days after impact injury. Muscle tissue was analyzed using unbiased, data-independent acquisition LC-MS/MS. We identified 770 reviewed proteins in the muscle tissue, 296 of which were differentially abundant between the control and injury groups (P ≤ 0.05). Around 50 proteins showed large differences (≥10-fold) or a distinct pattern of abundance after injury. These included proteins that have not been identified previously in injured muscle, such as ferritin light chain 1, fibrinogen γ-chain, fibrinogen β-chain, osteolectin, murinoglobulin-1, T-kininogen 2, calcium-regulated heat-stable protein 1, macrophage-capping protein, retinoid-inducible serine carboxypeptidase, ADP-ribosylation factor 4, Thy-1 membrane glycoprotein, and ADP-ribosylation factor-like protein 1. Some proteins increased between 6 h and 14 days, whereas other proteins increased in a more delayed pattern at 7 days after injury. Bioinformatic analysis revealed that various biological processes, including regulation of blood coagulation, fibrinolysis, regulation of wound healing, tissue regeneration, acute inflammatory response, and negative regulation of the immune effector process, were enriched in injured muscle tissue. This study advances the understanding of early muscle healing after muscle injury and lays a foundation for future mechanistic studies on interventions to treat muscle injury.

Lack of Thy1 defines a pathogenic fraction of cardiac fibroblasts in heart failure

In response to heart injury, inflammation, or mechanical overload, quiescent cardiac fibroblasts (CFs) can become activated myofibroblasts leading to pathological matrix remodeling and decline in cardiac function. Specific targeting of fibroblasts may thus enable new therapeutic strategies to delay or reverse the progression of heart failure and cardiac fibrosis. However, it remains unknown if all CFs are equally responsive to specific pathological insults and if there exist sub-populations of resident fibroblasts in the heart that have distinctive pathogenic phenotypes. Here, we show that in response to transverse aortic constriction (TAC)-induced heart failure, previously uncharacterized Thy1^neg (Thy1-/MEFSK4+/CD45-/CD31-) fraction of mouse ventricular fibroblasts became more abundant and attained a more activated, pro-fibrotic myofibroblast phenotype compared to Thy1^Pos fraction. In a tissue-engineered 3D co-culture model of healthy cardiomyocytes and freshly isolated CFs, Thy1^neg CFs from TAC hearts significantly decreased cardiomyocyte contractile function and calcium transient amplitude, and increased extracellular collagen deposition yielding a profibrotic heart tissue phenotype. In vivo, mice with global knockout of Thy1 developed more severe cardiac dysfunction and fibrosis in response to TAC-induced heart failure than wild-type mice. Taken together, our studies identify cardiac myofibroblasts lacking Thy1 as a pathogenic CF fraction in cardiac fibrosis and suggest important roles of Thy1 in pathophysiology of heart failure.

Cell-surface markers identify tissue resident multipotential stem/stromal cell subsets in synovial intimal and sub-intimal compartments with distinct chondrogenic properties

OBJECTIVE

Synovium contains multipotent progenitor/stromal cells (MPCs) with potential to participate in cartilage repair. Understanding the identity of these MPCs will allow their therapeutic potential to be fully exploited. Hence this study aimed to identify primary synovial MPCs and characterize them in the context of cartilage regeneration.

METHODS

Primary MPC/MPC-subset specific markers in synovium were identified by FACS analysis of uncultured cells. MPC-subsets from human synovium obtained from patients undergoing total knee arthroplasty were FACS sorted, cultured, immunophenotyped and chondrogenically differentiated. The anatomical localization of MPCs in synovium was examined using immunohistochemistry. Finally, the presence of these MPC subsets in healthy synovium obtained from human organ donors was examined.

RESULTS

A combination of CD45, CD31, CD73 and CD90 can isolate two distinct MPC-subsets in synovium. These MPC-subsets, freshly isolated from synovium, did not express CD45 or CD31, but expressed CD73. Additionally, a sub-population of CD73⁺ cells also expressed CD90. CD45^-CD31^-CD73⁺CD90^- cells were significantly more chondrogenic than CD45^-CD31^-CD73⁺CD90⁺ cells in the presence of TGFβ1. Interestingly, reduced chondrogenic ability of CD73⁺CD90⁺ cells could be reversed by the addition of BMP2, showing discrete chondrogenic factor requirements by distinct cell-subsets. In addition, these MPCs had distinct anatomical localization; CD73 was expressed both in intimal and sub-intimal region while CD90 was enriched in the sub-intimal region. We further demonstrated that these subsets are also present in healthy synovium.

CONCLUSIONS

We provide indications that primary MPCs in synovial intima and sub-intima are phenotypically and functionally distinct with different chondrogenic properties.

Enhancing FcγR-mediated antibody effector function during persistent viral infection

Persistent viral infections can interfere with FcγR-mediated antibody effector functions by excessive immune complex (IC) formation, resulting in resistance to therapeutic FcγR-dependent antibodies. We and others have previously demonstrated that mice persistently infected with lymphocytic choriomeningitis virus (LCMV) are resistant to a wide range of depleting antibodies due to excessive IC formation. Here, we dissect the mechanisms by which two depleting antibodies overcome the obstacle of endogenous ICs and achieve efficient target cell depletion in persistently infected mice. Efficient antibody-mediated depletion during persistent LCMV infection required increased levels of antibody bound to target cells or use of afucosylated antibodies with increased affinity for FcγRs. Antibodies targeting the highly expressed CD90 antigen or overexpressed human CD20 efficiently depleted their target cells in naïve and persistently infected mice, whereas antibodies directed against less abundant antigens failed to deplete their target cells during persistent LCMV infection. In addition, we demonstrate the superior activity of afucosylated antibodies in the presence of endogenous ICs. We generated afucosylated antibodies directed against CD4 and CD8α, which, in contrast to their parental fucosylated versions, efficiently depleted their respective target cells in persistently infected mice. Efficient antibody-mediated depletion can thus be achieved if therapeutic antibodies can outcompete endogenous ICs for access to FcγRs either by targeting highly expressed antigens or by increased affinity for FcγRs. Our findings have implications for the optimization of therapeutic antibodies and provide strategies to allow efficient FcγR engagement in the presence of competing endogenous ICs in persistent viral infections, autoimmune diseases, and cancer.

Ageing characteristics of bone indicated by transcriptomic and exosomal proteomic analysis of cortical bone cells

BACKGROUND

Degenerative changes in the skeleton play an important role in ageing. As the foremost sensors and orchestrators of bone remodelling, osteocytes contribute significantly to the health of the skeleton. Embedded in a mineralized bone matrix, the osteocyte network and the surrounding lacunar canaliculae work together as a functional syncytium-the osteocytic lacunar-canalicular system (OLCS). However, changes in the OLCS during ageing and related mechanisms cannot be fully understood by using traditional histological analysis.

METHODS

To link the phenotypes of aged osteocytes and their functional changes during ageing, we analysed the changes in the gene expression profiles of bone cells and the proteomic profiles of OLCS exosomes derived from aged and young cortical bone.

RESULTS

Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of differentially expressed genes (DEGs) suggested that a decline in cell energy metabolism and an increased level of the proinflammatory state are major characteristics of bone ageing. Moreover, some DEGs were key regulators of bone mechanical sensation and bone remodelling, which are indicative of reduced bone-specific function with age. Further, the identified proteins in OLCS exosomes showed potential changes in the secretory function bone. Compared with young controls, the decreased functional proteins in aged OLCS exosomes were enriched mainly in GO terms that included regulating bone development and remodelling, cell-matrix adhesion, and cell clearance and homeostasis. Notably, several functions of exosomal proteins of the aged group revealed potential new roles, such as regulating innate and adaptive immunity, wound healing, and angiogenesis and eliminating oxidative stress.

CONCLUSION

The information obtained from bone cells and OLCS exosomes will help us discover new features of bone ageing.

Genome-wide association study of an unusual dolphin mortality event reveals candidate genes for susceptibility and resistance to cetacean morbillivirus

Infectious diseases are significant demographic and evolutionary drivers of populations, but studies about the genetic basis of disease resistance and susceptibility are scarce in wildlife populations. Cetacean morbillivirus (CeMV) is a highly contagious disease that is increasing in both geographic distribution and incidence, causing unusual mortality events (UME) and killing tens of thousands of individuals across multiple cetacean species worldwide since the late 1980s. The largest CeMV outbreak in the Southern Hemisphere reported to date occurred in Australia in 2013, where it was a major factor in a UME, killing mainly young Indo-Pacific bottlenose dolphins (Tursiops aduncus). Using cases (nonsurvivors) and controls (putative survivors) from the most affected population, we carried out a genome-wide association study to identify candidate genes for resistance and susceptibility to CeMV. The genomic data set consisted of 278,147,988 sequence reads and 35,493 high-quality SNPs genotyped across 38 individuals. Association analyses found highly significant differences in allele and genotype frequencies among cases and controls at 65 SNPs, and Random Forests conservatively identified eight as candidates. Annotation of these SNPs identified five candidate genes (MAPK8, FBXW11, INADL, ANK3 and ACOX3) with functions associated with stress, pain and immune responses. Our findings provide the first insights into the genetic basis of host defence to this highly contagious disease, enabling the development of an applied evolutionary framework to monitor CeMV resistance across cetacean species. Biomarkers could now be established to assess potential risk factors associated with these genes in other CeMV-affected cetacean populations and species. These results could also possibly aid in the advancement of vaccines against morbilliviruses.

Thy1 (CD90) expression is regulated by DNA methylation during adipogenesis

The obesity epidemic is developing into the most costly health problem facing the world. Obesity, characterized by excessive adipogenesis and enlarged adipocytes, promotes morbidities, such as diabetes, cardiovascular disease, and cancer. Regulation of adipogenesis is critical to our understanding of how fat cell formation causes obesity and associated health problems. Thy1 (also called CD90), a widely used stem cell marker, blocks adipogenesis and reduces lipid accumulation. Thy1-knockout mice are prone to diet-induced obesity. Although the importance of Thy1 in adipogenesis and obesity is now evident, how its expression is regulated is not. We hypothesized that DNA methylation has a role in promoting adipogenesis and affects Thy1 expression. Using the methylation inhibitor 5-aza-2'-deoxycytidine (5-aza-dC), we investigated whether DNA methylation alters Thy1 expression during adipogenesis in both mouse 3T3-L1 preadipocytes and mouse mesenchymal stem cells. Thy1 protein and mRNA levels were decreased dramatically during adipogenesis. However, 5-aza-dC treatment prevented that phenomenon. Methylation-sensitive pyrosequencing analysis showed that CpG sites at the Thy1 locus have increased methylation during adipogenesis, as well as increased methylation in adipose tissue from diet-induced obese mice. These new findings highlight the potential role of Thy1 and DNA methylation in adipogenesis and obesity.-Flores, E. M., Woeller, C. F., Falsetta, M. L., Susiarjo, M., Phipps, R. P. Thy1 (CD90) expression is regulated by DNA methylation during adipogenesis.

Thy-1 as an Integrator of Diverse Extracellular Signals

Thy-1 was discovered over 50 years ago, and in that time investigators from a broad variety of fields have described numerous and heterogeneous biological functions of Thy-1 in multiple contexts. As an outwardly facing cell surface molecule, it is well positioned to receive extracellular signals; previously reviewed studies have confirmed an important role in cell-cell and cell-matrix adhesion, cell migration, and regulation of outside-in signaling. More recent studies reviewed here expand the repertoire of Thy-1 effects on signaling pathways, and reveal novel roles in mechanotransduction, cellular differentiation, viral entry, and extracellular vesicle binding and internalization. All of these studies contribute to understanding Thy-1 as a context-dependent integrator of a diverse range of extracellular information, and provide impetus for further studies, some of which are suggested here.

Panoptic imaging of transparent mice reveals whole-body neuronal projections and skull-meninges connections

Analysis of entire transparent rodent bodies after clearing could provide holistic biological information in health and disease, but reliable imaging and quantification of fluorescent protein signals deep inside the tissues has remained a challenge. Here, we developed vDISCO, a pressure-driven, nanobody-based whole-body immunolabeling technology to enhance the signal of fluorescent proteins by up to two orders of magnitude. This allowed us to image and quantify subcellular details through bones, skin and highly autofluorescent tissues of intact transparent mice. For the first time, we visualized whole-body neuronal projections in adult mice. We assessed CNS trauma effects in the whole body and found degeneration of peripheral nerve terminals in the torso. Furthermore, vDISCO revealed short vascular connections between skull marrow and brain meninges, which were filled with immune cells upon stroke. Thus, our new approach enables unbiased comprehensive studies of the interactions between the nervous system and the rest of the body.

Thy-1 (CD90) Signaling Preferentially Promotes RORγt Expression and a Th17 Response

Thy-1 (CD90) is a glycosylphosphatidylinositol-anchored protein (GPI-AP) with signaling properties that is abundant on mouse T cells. Upon antibody-mediated crosslinking, Thy-1 provides a T cell receptor (TcR)-like signal that is sufficient to drive CD4⁺ T cell proliferation and differentiation into effector cells when costimulatory signals are provided by syngeneic lipopolysaccharide-matured bone marrow-derived dendritic cells. In this study, we investigated the impact of Thy-1 signaling on the production of the T helper (Th) cell subset-associated cytokines, interferon (IFN) γ, interleukin (IL)-4 and IL-17A, as well as the in vitro polarization of highly purified resting CD4⁺ T cells into Th1, Th2, and Th17 cells. Although CD8⁺ T cells expressed more Thy-1 than CD4⁺ T cells, both T cell populations were equally responsive to Thy-1 stimulation. In contrast to TcR stimulation of CD3⁺ T cells, which favored IFNγ and IL-4 production, Thy-1 signaling favored IL-17 synthesis, indicating a previously unidentified difference between the consequences of Thy-1 and TcR signal transduction. Moreover, Thy-1 signaling preferentially induced the Th17-associated transcription factor RORγt in CD4⁺ T cells. As with TcR signaling, Thy-1 stimulation of CD4⁺ T cells under the appropriate polarizing conditions resulted in Th1, Th2 or Th17 cell induction; however, Thy-1 stimulation induced nearly 7- and 2-fold more IL-4 and IL-17A, respectively, but only slightly more IFNγ. The ability to provide a TcR-like signal capable of promoting T helper cell differentiation and cytokine synthesis was not common to all GPI-APs since cross-linking of Ly6A/E with mitogenic mAb did not promote substantial production of IFNγ, IL-4 or IL-17, although there was a substantial proliferative response. The preferential induction of RORγt and Th17 cytokine synthesis as a consequence of Thy-1 signaling suggests a default T helper cell response that may enhance host defense against extracellular pathogens.

PMA inhibits endothelial cell migration through activating the PKC-δ/Syk/NF-κB-mediated up-regulation of Thy-1

We previously showed that overexpression of Thy-1 inhibited and knock-down of Thy-1 enhanced endothelial cell migration. Here, we used phorbol-12-myristate-13-acetate (PMA) as an inducer for Thy-1 expression to investigate molecular mechanisms underlying Thy-1 up-regulation. Our data showed that increased levels of Thy-1 mRNA and protein in endothelial cells were observed at 14–18 hours and 20–28 hours after PMA treatment, respectively. Treatment with PMA for 32 hours induced Thy-1 up-regulation and inhibited capillary-like tube formation and endothelial cell migration. These effects were abolished by Röttlerin (a PKC-δ inhibitor), but not Gö6976 (a PKC-α/β inhibitor). Moreover, pre-treatment with Bay 61–3606 (a Syk inhibitor) or Bay 11-7082 (a NF-κB inhibitor) abolished the PMA-induced Thy-1 up-regulation and migration inhibition in endothelial cells. Using the zebrafish model, we showed that PMA up-regulated Thy-1 and inhibited angiogenesis through the PKC-δ-mediated pathway. Surprisingly, we found that short-term (8–10 hours) PMA treatment enhanced endothelial cell migration. However, this effect was not observed in PMA-treated Thy-1-overexpressed endothelial cells. Taken together, our results suggest that PMA initially enhanced endothelial cell migration, subsequently activating the PKC-δ/Syk/NF-κB-mediated pathway to up-regulate Thy-1, which in turn inhibited endothelial cell migration. Our results also suggest that Thy-1 might play a role in termination of angiogenesis.

Serially transplantable mammary epithelial cells express the Thy-1 antigen

BACKGROUND

Recent studies in murine mammary tissue have identified functionally distinct cell populations that may be isolated by surface phenotype or lineage tracing. Previous groups have shown that CD24^medCD49f^high cells enriched for long-lived mammary epithelial cells can be serially transplanted.

METHODS

Flow cytometry-based enrichment of distinct phenotypic populations was assessed for their gene expression profiles and functional proliferative attributes in vitro and in vivo.

RESULTS

Here, we show Thy-1 is differentially expressed in the CD24^medCD49f^high population, which allowed us to discern two functionally different populations. The Thy-1⁺CD24^medCD49f^high phenotype contained the majority of the serially transplantable epithelial cells. The Thy-1^-CD24^medCD49f^high phenotype contains a rare progenitor population that is able to form primary mammary outgrowths with significantly decreased serial in vivo transplantation potential.

CONCLUSIONS

Therefore, Thy-1 expression in the immature cell compartment is a useful tool to study the functional heterogeneity that drives mammary gland development and has implications for disease etiology.

Critical View on Mesenchymal Stromal Cells in Regenerative Medicine

SIGNIFICANCE

The belief in the potency of stem cells has resulted in the medical applications of numerous cell types for organ repair, often with the low adherence to methodological stringency. Such uncritical enthusiasm is mainly presented in the approaches employing so-called mesenchymal stem cells (MSC), for the treatment of numerous, unrelated conditions. However, it should be stressed that such broad clinical applications of MSC are mostly based on the belief that MSC can efficiently differentiate into multiple cell types, not only osteoblasts, chondrocytes and adipose cells. Recent Advances: Studies employing lineage tracing established more promising markers to characterize MSC identity and localization in vivo and confirmed the differences between MSC isolated from various organs. Furthermore, preclinical and clinical experiments proved that transdifferentiation of MSC is unlikely to contribute to repair of numerous tissues, including the heart. Therefore, the salvage hypotheses, like MSC fusion with cells in target organs or the paracrine mechanisms, were proposed to justify the widespread application of MSC and to explain transient, if any, effects.

CRITICAL ISSUES

The lack of standardization concerning the cells markers, their origin and particularly the absence of stringent functional characterization of MSC, leads to propagation of the worrying hype despite the lack of convincing therapeutic efficiency of MSC.

FUTURE DIRECTIONS

The adherence to rigorous methodological rules is necessary to prevent the application of procedures which can be dangerous for patients and scientific research on the medical application of stem cells. Antioxid. Redox Signal. 00, 000-000.

A Profibrotic Phenotype in Naïve and in Fibrotic Lung Myofibroblasts Is Governed by Modulations in Thy-1 Expression and Activation

Lung fibrosis is characterized by abnormal accumulation of Thy-deficient fibroblasts in the interstitium of the alveolar space. We have previously shown in bleomycin-treated chimeric Thy1-deficient mice with wild-type lymphocytes that Thy1-deficient fibroblasts accumulate and promote fibrosis and an “inflammation-free” environment. Here, we aimed to identify the critical effects of Thy1, or the absence of Thy1, in lung myofibroblast profibrotic functions, particularly proliferation and collagen deposition. Using specific Thy1 siRNA in Thy1-positive cells, Thy1 knockout cells, Thy1 cDNA expression vector in Thy1-deficient cells, and Thy1 cross-linking, we evaluated cell proliferation (assessed by cell mass and BrdU uptake), differentiation (using immunofluorescence), and collagen deposition (using Sircol assay). We found that myofibroblast Thy1 cross-linking and genetic manipulation modulate cell proliferation and expression of Fgf (fibroblast growth factor) and Angtl (angiotensin) receptors (using qPCR) that are involved in myofibroblast proliferation, differentiation, and collagen deposition. In conclusion, lung myofibroblast downregulation of Thy1 expression is critical to increase proliferation, differentiation, and collagen deposition.

Circulating Tumor Cells Detected by the Expression of Cancer Stem Cell Markers CD90 and CD44 in Patients With Esophageal Cancer

Background

Epithelial cell adhesion molecule (EpCAM) is a marker for circulating tumor cells (CTCs) in various types of cancer. Cell surface antigens, such as CD90 and CD44, have been reported to be cancer stem cell (CSC) markers in esophageal squamous cell carcinoma (ESCC). The aim of this study was to assess the use of CD90 and CD44 as markers to identify clinically significant CTC subpopulations in ESCC.

Methods

We collected 3 mL of peripheral blood from 10 ESCC patients and 10 healthy volunteers to detect combined expression of EpCAM, CD90, and CD40 using flow cytometry.

Results

The number of EpCAM-positive cell counts (average ± SD) in the patients was significantly higher than healthy volunteers (29.1 ± 35.9 and 2.3 ± 2.5, P = 0.001). The proportions (average ±SD) of CD90- and CD44-positive cells in EpCAM-positive cells were 45.7% ± 42.4% and 98.7% ± 2.7%, respectively. EpCAM-positive/CD44-positive CTC counts, which was equivalent to EpCAM-positive CTC counts, correlated with pathologic V factors in the resected primary tumors (P &gt; 0.01). EpCAM-positive/CD90-positive CTC counts, but not EpCAM-positive/CD90-negative CTC counts, correlated with pathologic V factors in the resected primary tumors (P = 0.01). Our results suggested that combined expression of EpCAM and CD90 may useful to detect CTC subsets, which have highly metastatic features in ESCC. CD44, on the other hand, is equivalent to EpCAM as a marker to detect CTCs in ESCC.

Thy-1 stimulation of mouse T cells induces a delayed T cell receptor-like signal that results in Ca2+‑independent cytotoxicity

Antibody-mediated crosslinking of Thy-1 [also known as cluster of differentiation (CD)90], results in a T cell receptor (TcR)‑like signal; however, the impact of Thy‑1 stimulation in comparison to TcR stimulation on T cell activation and effector function has yet to be fully elucidated. In the present study, the outcome of Thy‑1‑ and TcR‑induced stimulation of T cells was investigated in mice, using fragment crystalizable (Fc) receptor‑bound antibodies and costimulatory signals provided by syngeneic lipopolysaccharide‑matured bone marrow‑derived dendritic cells. Compared with TcR signaling, Thy‑1 signaling initiated a less robust proliferative response in T cells, as determined by tritiated‑thymidine incorporation. In addition, enzyme‑linked immunosorbent assays revealed that interleukin‑2 production was reduced, and the expression of CD25 and cyclin D3 was weaker in Thy‑1‑stimulated cells, as determined by western blotting; however, the expression of cyclin‑dependent kinase 6 was similar to that in TcR‑induced T cells. Furthermore, western blotting demonstrated that the phosphorylation of ζ-chain‑associated protein kinase 70 and extracellular signal‑regulated kinase 1/2 was delayed following Thy‑1 stimulation. DNA fragmentation assays revealed that cytotoxic effector function was also slower to develop in Thy‑1‑stimulated T cells, required more time to be effective and was largely Ca2+‑independent; these findings suggested that Fas ligand rather than granule‑associated perforin was involved in T cell effector function. In conclusion, the present results suggested that Thy‑1 signaling may contribute to the regulation of T cell homeostasis and the development of non‑specific T cell‑mediated cytotoxicity. However, further studies are required to elucidate the exact physiological roles of TcR‑like signals that result from Thy‑1 crosslinking and to investigate the molecular mechanisms that are involved.

Dendritic cells that phagocytose apoptotic macrophages loaded with mycobacterial antigens activate CD8 T cells via cross-presentation

While homeostatic apoptosis is immunologically silent, macrophage apoptosis during Mycobacterium tuberculosis infection can potentially induce an immune response against the mycobacteria. To examine the role of dendritic cells in this response, macrophage apoptosis was induced by incubating the macrophage with cell wall extracts of mycobacteria expressing LpqH. The apoptogenic proteins of the cell wall extracts were engulfed by the macrophage and then were translocated from the cytosol to the nuclei of the dying cells. Dendritic cells that engulfed the apoptotic macrophages acquired an immunogenic phenotype that included upregulation of MHC-I, increased expression of the costimulatory molecules, CD40, CD80, and CD86, and increased production of IL-12, IL-10, TNF-α, and TGF-β. In addition, the dendritic cells triggered a proliferative response of CD8+ T cells with IFN-γ production via cross-presentation. Taken together, these findings support a model in which phagocytosis of whole apoptotic cells carrying mycobacterial antigens promotes a potentially protective immune response.

Isolation of Primary Murine Retinal Ganglion Cells (RGCs) by Flow Cytometry

Neurodegenerative diseases often have a devastating impact on those affected. Retinal ganglion cell (RGC) loss is implicated in an array of diseases, including diabetic retinopathy and glaucoma, in addition to normal aging. Despite their importance, RGCs have been extremely difficult to study until now due in part to the fact that they comprise only a small percentage of the wide variety of cells in the retina. In addition, current isolation methods use intracellular markers to identify RGCs, which produce non-viable cells. These techniques also involve lengthy isolation protocols, so there is a lack of practical, standardized, and dependable methods to obtain and isolate RGCs. This work describes an efficient, comprehensive, and reliable method to isolate primary RGCs from mice retinae using a protocol based on both positive and negative selection criteria. The presented methods allow for the future study of RGCs, with the goal of better understanding the major decline in visual acuity that results from the loss of functional RGCs in neurodegenerative diseases.

Desipramine decreases expression of human and murine indoleamine-2,3-dioxygenases

Abundant evidence connects depression symptomology with immune system activation, stress and subsequently elevated levels of kynurenine. Anti-depressants, such as the tricyclic norepinephrine/serotonin reuptake inhibitor desipramine (Desip), were developed under the premise that increasing extracellular neurotransmitter level was the sole mechanism by which they alleviate depressive symptomologies. However, evidence suggests that anti-depressants have additional actions that contribute to their therapeutic potential. The Kynurenine Pathway produces tryptophan metabolites that modulate neurotransmitter activity. This recognition identified another putative pathway for anti-depressant targeting. Considering a recognized role of the Kynurenine Pathway in depression, we investigated the potential for Desip to alter expression of rate-limiting enzymes of this pathway: indoleamine-2,3-dioxygenases (Ido1 and Ido2). Mice were administered lipopolysaccharide (LPS) or synthetic glucocorticoid dexamethasone (Dex) with Desip to determine if Desip alters indoleamine-dioxygenase (DO) expression in vivo following a modeled immune and stress response. This work was followed by treating murine and human peripheral blood mononuclear cells (PBMCs) with interferon-gamma (IFNγ) and Desip. In vivo: Desip blocked LPS-induced Ido1 expression in hippocampi, astrocytes, microglia and PBMCs and Ido2 expression by PBMCs. Ex vivo: Desip decreased IFNγ-induced Ido1 and Ido2 expression in murine PBMCs. This effect was directly translatable to the human system as Desip decreased IDO1 and IDO2 expression by human PBMCs. These data demonstrate for the first time that an anti-depressant alters expression of Ido1 and Ido2, identifying a possible new mechanism behind anti-depressant activity. Furthermore, we propose the assessment of PBMCs for anti-depressant responsiveness using IDO expression as a biomarker.

Immune Protection of Retroviral Vectors Upon Molecular Painting with the Complement Regulatory Protein CD59

Glycosylphosphatidylinositol anchoring is a type of post-translational modification that allows proteins to be presented on the exterior side of the cell membrane. Purified glycosylphosphatidylinositol-anchored protein can spontaneously re-insert into lipid bilayer membranes in a process termed Molecular Painting. Here, we demonstrate the possibility of inserting purified, recombinant CD59 into virus particles produced from a murine retroviral producer cell line. CD59 is a regulator of the complement system that helps protect healthy cells from the lytic activity of the complement cascade. In this study, we could show that Molecular Painting confers protection from complement activity upon murine retroviral vector particles. Indeed, increased infectivity of CD59-modified virus particles was observed upon challenge with human serum, indicating that Molecular Painting is suitable for modulating the immune system in gene therapy or vaccination applications.

Systemic Immunity Is Required for Effective Cancer Immunotherapy

Immune responses involve coordination across cell types and tissues. However, studies in cancer immunotherapy have focused heavily on local immune responses in the tumor microenvironment. To investigate immune activity more broadly, we performed an organism-wide study in genetically engineered cancer models using mass cytometry. We analyzed immune responses in several tissues after immunotherapy by developing intuitive models for visualizing single-cell data with statistical inference. Immune activation was evident in the tumor and systemically shortly after effective therapy was administered. However, during tumor rejection, only peripheral immune cells sustained their proliferation. This systemic response was coordinated across tissues and required for tumor eradication in several immunotherapy models. An emergent population of peripheral CD4 T cells conferred protection against new tumors and was significantly expanded in patients responding to immunotherapy. These studies demonstrate the critical impact of systemic immune responses that drive tumor rejection.

Molecular Cloning and Expression Analysis of Pig Cd90

The CD90 (Thy-1) is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein that transfers signals involved in many biological events including cell activation, cell migration, cell adhesion, and tumor suppression. In this study, we cloned pig CD90 cDNA and determined its complete cDNA sequence. Pig CD90 cDNA contained an open reading frame (486 bp) encoding 161 amino acids with three putative N-glycosylation sites and four well-conserved cysteine residues, which form a possible disulfide bond within the extracellular domain among mammalian species. Pig CD90 mRNA was detected in various tissues, indicating the multicellular functions of CD90 in pigs. Flow cytometry analyses demonstrated that anti-human CD90 antibody recognizes a pig CD90 on the cell surface. Moreover, immunohistochemistry analysis revealed that CD90 expression is widely diffused in several pig tissues. Further studies will be necessary to define the functional contribution of CD90 during specific infectious diseases in pigs.

Investigation of the Cell Surface Proteome of Human Periodontal Ligament Stem Cells

The present study examined the cell surface proteome of human periodontal ligament stem cells (PDLSC) compared to human fibroblasts. Cell surface proteins were prelabelled with CyDye before processing to extract the membrane lysates, which were separated using 2D electrophoresis. Selected differentially expressed protein “spots” were identified using Mass spectrometry. Four proteins were selected for validation: CD73, CD90, Annexin A2, and sphingosine kinase 1 previously associated with mesenchymal stem cells. Flow cytometric analysis found that CD73 and CD90 were highly expressed by human PDLSC and gingival fibroblasts but not by keratinocytes, indicating that these antigens could be used as potential markers for distinguishing between mesenchymal cells and epithelial cell populations. Annexin A2 was also found to be expressed at low copy number on the cell surface of human PDLSC and gingival fibroblasts, while human keratinocytes lacked any cell surface expression of Annexin A2. In contrast, sphingosine kinase 1 expression was detected in all the cell types examined using immunocytochemical analysis. These proteomic studies form the foundation to further define the cell surface protein expression profile of PDLSC in order to better characterise this cell population and help develop novel strategies for the purification of this stem cell population.

CD90 and CD24 Co-Expression Is Associated with Pancreatic Intraepithelial Neoplasias

Thy-1 (CD90) has been shown to be a potential marker for several different types of cancer. However, reports on CD90 expression in pancreatic intraepithelial neoplasia (PanIN) lesions are still limited where PanINs are the most important precursor lesion of pancreatic ductal adenocarcinoma (PDAC). Herein, we investigate candidate markers for PanIN lesions by examining the distribution and trend of CD90 and CD24 expression as well as their co-expression in various stages of PanINs. Thirty cases of PanINs, which were confirmed histopathologically and clinically, were used to evaluate protein expression of CD90 and CD24 by immunofluoresence double staining. CD90 was found to be mainly expressed in stroma around lesion ducts while not observed in acini and islets in PanINs. CD90 also showed increased expression in PanIN III compared to PanIN III. CD24 was mainly present in the cytoplasm and membrane of pancreatic ductal epithelia, especially in the apical epithelium of the duct. CD24 had higher expression in PanIN III compared with PanIN IIIIII or PanIN III. CD90 was expressed around CD24 sites, but there was little overlap between cells that expressed each of these proteins. A correlation analysis showed that these two proteins have a moderate relationship with PanIN stages respectively. These results suggest that co-expression of CD90 and CD24 may have an important role in the development and progression of PanINs, which is also conducive to early detection and treatment of PDAC.

Isolation and Molecular Profiling of Primary Mouse Retinal Ganglion Cells: Comparison of Phenotypes from Healthy and Glaucomatous Retinas

Loss of functional retinal ganglion cells (RGC) is an element of retinal degeneration that is poorly understood. This is in part due to the lack of a reliable and validated protocol for the isolation of primary RGCs. Here we optimize a feasible, reproducible, standardized flow cytometry-based protocol for the isolation and enrichment of homogeneous RGC with the Thy1.2(hi)CD48(neg)CD15(neg)CD57(neg) surface phenotype. A three-step validation process was performed by: (1) genomic profiling of 25-genes associated with retinal cells; (2) intracellular labeling of homogeneous sorted cells for the intracellular RGC-markers SNCG, brain-specific homeobox/POU domain protein 3A (BRN3A), TUJ1, and RNA-binding protein with multiple splicing (RBPMS); and (3) by applying the methodology on RGC from a mouse model with elevated intraocular pressure (IOP) and optic nerve damage. Use of primary RGC cultures will allow for future careful assessment of important cell specific pathways in RGC to provide mechanistic insights into the declining of visual acuity in aged populations and those suffering from retinal neurodegenerative diseases.

p75 neurotrophin receptor expression is a characteristic of the mitotically quiescent cancer stem cell population present in esophageal squamous cell carcinoma

Mitotically quiescent cancer stem cells (CSC) are hypothesized to exhibit a more aggressive phenotype involving greater therapeutic resistance and metastasis. The aim of our study was to develop a method for identifying quiescent CSC in esophageal squamous cell carcinoma (ESCC) based on their expression of the p75 neurotrophin receptor (p75NTR) and other proposed CSC markers, such as CD44 and CD90. Double immunostaining of surgical ESCC specimens revealed that the mean Ki-67-labeling index of the p75NTR-positive cells was significantly lower than that of the p75NTR-negative cells. Real-time PCR analysis of sorted fractions of ESCC cell lines (KYSE cells) revealed that stem cell-related genes (Nanog, p63 and Bmi-1) and epithelial-mesenchymal transition (EMT)-related genes (N-cadherin and fibronectin) were expressed at significantly higher levels in the p75NTR-positive fractions than in the CD44-positive or CD90-positive fractions. In addition, the p75NTR-positive fractions exhibited significantly higher colony formation in vitro, significantly enhanced tumor formation in mice, and significantly greater chemoresistance against cisplatin (CDDP) than the CD44‑positive or CD90‑positive fractions. Furthermore, in both the cultured cells and those from the mouse xenograft tumors, the p75NTR‑positive/CD44-negative and p75NTR‑positive/CD90-negative KYSE cell fractions contained significantly higher proportions of mitotically quiescent cells. These results suggest that the mitotically quiescent CSC population in ESCC can be identified and isolated based on their p75NTR expression, providing researchers with a novel diagnostic and therapeutic target.