Crosstalk between T lymphocyte and extracellular matrix in tumor microenvironment

The extracellular matrix (ECM) is a complex three-dimensional structure composed of proteins, glycans, and proteoglycans, constituting a critical component of the tumor microenvironment. Complex interactions among immune cells, extracellular matrix, and tumor cells promote tumor development and metastasis, consequently influencing therapeutic efficacy. Hence, elucidating these interaction mechanisms is pivotal for precision cancer therapy. T lymphocytes are an important component of the immune system, exerting direct anti-tumor effects by attacking tumor cells or releasing lymphokines to enhance immune effects. The ECM significantly influences T cells function and infiltration within the tumor microenvironment, thereby impacting the behavior and biological characteristics of tumor cells. T cells are involved in regulating the synthesis, degradation, and remodeling of the extracellular matrix through the secretion of cytokines and enzymes. As a result, it affects the proliferation and invasive ability of tumor cells as well as the efficacy of immunotherapy. This review discusses the mechanisms underlying T lymphocyte-ECM interactions in the tumor immune microenvironment and their potential application in immunotherapy. It provides novel insights for the development of innovative tumor therapeutic strategies and drug.

Granzymes in health and diseases: the good, the bad and the ugly

Granzymes are a family of serine proteases, composed of five human members: GA, B, H, M and K. They were first discovered in the 1980s within cytotoxic granules released during NK cell- and T cell-mediated killing. Through their various proteolytic activities, granzymes can trigger different pathways within cells, all of which ultimately lead to the same result, cell death. Over the years, the initial consideration of granzymes as mere cytotoxic mediators has changed due to surprising findings demonstrating their expression in cells other than immune effectors as well as new intracellular and extracellular activities. Additional roles have been identified in the extracellular milieu, following granzyme escape from the immunological synapse or their release by specific cell types. Outside the cell, granzyme activities mediate extracellular matrix alteration via the degradation of matrix proteins or surface receptors. In certain contexts, these processes are essential for tissue homeostasis; in others, excessive matrix degradation and extensive cell death contribute to the onset of chronic diseases, inflammation, and autoimmunity. Here, we provide an overview of both the physiological and pathological roles of granzymes, highlighting their utility while also recognizing how their unregulated presence can trigger the development and/or worsening of diseases.

Mechanotransduction in response to ECM stiffening impairs cGAS immune signaling in tumor cells

The tumor microenvironment (TME) plays decisive roles in disabling T cell-mediated antitumor immunity, but the immunoregulatory functions of its biophysical properties remain elusive. Extracellular matrix (ECM) stiffening is a hallmark of solid tumors. Here, we report that the stiffened ECM contributes to the immunosuppression in TME via activating the Rho-associated coiled-coil-containing protein kinase (ROCK)-myosin IIA-filamentous actin (F-actin) mechanosignaling pathway in tumor cells to promote the generation of TRIM14-scavenging nonmuscle myosin heavy chain IIA (NMHC-IIA)-F-actin stress fibers, thus accelerating the autophagic degradation of cyclic guanosine monophosphate (GMP)-AMP synthase (cGAS) to deprive tumor cyclic GMP-AMP (cGAMP) and further attenuating tumor immunogenicity. Pharmacological inhibition of myosin IIA effector molecules with blebbistatin (BLEB) or the RhoA upstream regulator of this pathway with simvastatin (SIM) restored tumor-intrinsic cGAS-mediated cGAMP production and enhanced antitumor immunity. Our work identifies that ECM stiffness is an important biophysical cue to regulate tumor immunogenicity via the ROCK-myosin IIA-F-actin axis and that inhibiting this mechanosignaling pathway could boost immunotherapeutic efficacy for effective solid tumor treatment.

The extracellular matrix and the immune system: A mutually dependent relationship

For decades, immunologists have studied the role of circulating immune cells in host protection, with a more recent appreciation of immune cells resident within the tissue microenvironment and the intercommunication between nonhematopoietic cells and immune cells. However, the extracellular matrix (ECM), which comprises at least a third of tissue structures, remains relatively underexplored in immunology. Similarly, matrix biologists often overlook regulation of complex structural matrices by the immune system. We are only beginning to understand the scale at which ECM structures determine immune cell localization and function. Additionally, we need to better understand how immune cells dictate ECM complexity. This review aims to highlight the potential for biological discovery at the interface of immunology and matrix biology.

IL-22 regulates endometrial regeneration by enhancing tight junctions and orchestrating extracellular matrix

The uterine endometrium uniquely regenerates after menses, postpartum, or after breaks in the uterine layer integrity throughout women’s lives. Direct cell–cell contacts ensured by tight and adherens junctions play an important role in endometrial integrity. Any changes in these junctions can alter the endometrial permeability of the uterus and have an impact on the regeneration of uterine layers. Interleukin 22 (IL-22) is a cytokine that is recognized for its role in epithelial regeneration. Moreover, it is crucial in controlling the inflammatory response in mucosal tissues. Here, we studied the role of IL-22 in endometrial recovery after inflammation-triggered abortion. Fecundity of mice was studied in consecutive matings of the same animals after lipopolysaccharide (LPS) (10 µg per mouse)-triggered abortion. The fecundity rate after the second mating was substantially different between IL-22 knockout (IL-22^−/−) (9.1%) and wild-type (WT) (71.4%) mice (p < 0.05), while there was no difference between the groups in the initial mating, suggesting that IL-22 deficiency might be associated with secondary infertility. A considerable difference was observed between IL-22^−/− and WT mice in the uterine clearance following LPS-triggered abortion. Gross examination of the uteri of IL-22^−/− mice revealed non-viable fetuses retained inside the horns (delayed clearance). In contrast, all WT mice had completed abortion with total clearance after LPS exposure. We also discovered that IL-22 deficiency is associated with a decreased expression of tight junctions (claudin-2 and claudin-10) and cell surface pathogen protectors (mucin-1). Moreover, IL-22 has a role in the remodeling of the uterine tissue in the inflammatory environment by regulating epithelial–mesenchymal transition markers called E- and N-cadherin. Therefore, IL-22 contributes to the proper regeneration of endometrial layers after inflammation-triggered abortion. Thus, it might have a practical significance to be utilized as a treatment option postpartum (enhanced regeneration function) and in secondary infertility caused by inflammation (enhanced barrier/protector function).

Colon stroma mediates an inflammation-driven fibroblastic response controlling matrix remodeling and healing

Chronic inflammation is often associated with the development of tissue fibrosis, but how mesenchymal cell responses dictate pathological fibrosis versus resolution and healing remains unclear. Defining stromal heterogeneity and identifying molecular circuits driving extracellular matrix deposition and remodeling stands to illuminate the relationship between inflammation, fibrosis, and healing. We performed single-cell RNA-sequencing of colon-derived stromal cells and identified distinct classes of fibroblasts with gene signatures that are differentially regulated by chronic inflammation, including IL-11-producing inflammatory fibroblasts. We further identify a transcriptional program associated with trans-differentiation of mucosa-associated fibroblasts and define a functional gene signature associated with matrix deposition and remodeling in the inflamed colon. Our analysis supports a critical role for the metalloprotease Adamdec1 at the interface between tissue remodeling and healing during colitis, demonstrating its requirement for colon epithelial integrity. These findings provide mechanistic insight into how inflammation perturbs stromal cell behaviors to drive fibroblastic responses controlling mucosal matrix remodeling and healing.

TGFBI Production by Macrophages Contributes to an Immunosuppressive Microenvironment in Ovarian Cancer

The tumor microenvironment evolves during malignant progression, with major changes in nonmalignant cells, cytokine networks, and the extracellular matrix (ECM). In this study, we aimed to understand how the ECM changes during neoplastic transformation of serous tubal intraepithelial carcinoma lesions (STIC) into high-grade serous ovarian cancers (HGSOC). Analysis of the mechanical properties of human fallopian tubes (FT) and ovaries revealed that normal FT and fimbria had a lower tissue modulus, a measure of stiffness, than normal or diseased ovaries. Proteomic analysis of the matrisome fraction between FT, fimbria, and ovaries showed significant differences in the ECM protein TGF beta induced (TGFBI, also known as βig-h3). STIC lesions in the fimbria expressed high levels of TGFBI, which was predominantly produced by CD163-positive macrophages proximal to STIC epithelial cells. In vitro stimulation of macrophages with TGFβ and IL4 induced secretion of TGFBI, whereas IFNγ/LPS downregulated macrophage TGFBI expression. Immortalized FT secretory epithelial cells carrying clinically relevant TP53 mutations stimulated macrophages to secrete TGFBI and upregulated integrin αvβ3, a putative TGFBI receptor. Transcriptomic HGSOC datasets showed a significant correlation between TGFBI expression and alternatively activated macrophage signatures. Fibroblasts in HGSOC metastases expressed TGFBI and stimulated macrophage TGFBI production in vitro. Treatment of orthotopic mouse HGSOC tumors with an anti-TGFBI antibody reduced peritoneal tumor size, increased tumor monocytes, and activated β3-expressing unconventional T cells. In conclusion, TGFBI may favor an immunosuppressive microenvironment in STICs that persists in advanced HGSOC. Furthermore, TGFBI may be an effector of the tumor-promoting actions of TGFβ and a potential therapeutic target. SIGNIFICANCE: Analysis of ECM changes during neoplastic transformation reveals a role for TGFBI secreted by macrophages in immunosuppression in early ovarian cancer.

The Multiple Faces of Integrin-ECM Interactions in Inflammatory Bowel Disease

Inflammatory Bowel Disease (IBD) comprises a series of chronic and relapsing intestinal diseases, with Crohn's disease and ulcerative colitis being the most common. The abundant and uncontrolled deposition of extracellular matrix, namely fibrosis, is one of the major hallmarks of IBD and is responsible for the progressive narrowing and closure of the intestine, defined as stenosis. Although fibrosis is usually considered the product of chronic inflammation, the substantial failure of anti-inflammatory therapies to target and reduce fibrosis in IBD suggests that fibrosis might be sustained in an inflammation-independent manner. Pharmacological therapies targeting integrins have recently shown great promise in the treatment of IBD. The efficacy of these therapies mainly relies on their capacity to target the integrin-mediated recruitment and functionality of the immune cells at the damage site. However, by nature, integrins also act as mechanosensitive molecules involved in the intracellular transduction of signals and modifications originating from the extracellular matrix. Therefore, understanding integrin signaling in the context of IBD may offer important insights into mechanisms of matrix remodeling, which are uncoupled from inflammation and could underlie the onset and persistency of intestinal fibrosis. In this review, we present the currently available knowledge on the role of integrins in the etiopathogenesis of IBD, highlighting their role in the context of immune-dependent and independent mechanisms.

Rutin inhibited the advanced glycation end products-stimulated inflammatory response and extra-cellular matrix degeneration via targeting TRAF-6 and BCL-2 proteins in mouse model of osteoarthritis

BACKGROUND

Osteoarthritis (OA) is degenerative joint disorder mainly characterized by long-term pain with limited activity of joints, the disease has no effective preventative therapy. Rutin (RUT) is a flavonoid compound, present naturally. The flavonoid shows range of biological activities such as anti-inflammatory and anti-cancer effect. We screened RUT for its activity against osteoarthritis with in vivo and in vitro models of osteoarthritis.

METHODS

Animal model of OA was developed using C57BL/6 mice by surgical destabilization of medial meniscus. For in vitro studies the human articular cartilage tissues were used which were collected from osteoarthritis patients and were processed to isolate chondrocytes. The chondrocytes were submitted to advanced glycation end products (AGEs) for inducing osteoarthritis in vitro. Cell viability was done by CCK-8 assay, ELISA analysis for MMP13, collage II, PGE2, IL-6, TNF-α, ADAMTS-5 and MMP-13. Western blot analysis was done for expression of proteins and in silico analysis was done by docking studies.

RESULTS

Pretreatment of RT showed no cytotoxic effect and also ameliorated the AGE mediated inflammatory reaction on human chondrocytes in vitro. Treatment of RT inhibited the levels of COX-2 and iNOS in AGE exposed chondrocytes. RT decreased the AGE mediated up-regulation of IL-6, NO, TNF-α and PGE-2 in a dose dependent manner. Pretreatment of RT decreased the extracellular matrix degradation, inhibited expression of TRAF-6 and BCL-2 the NF-κB/MAPK pathway proteins. The treatment of RT in mice prevented the calcification of cartilage tissues, loss of proteoglycans and also halted the narrowing of joint space is mice subjected to osteoarthritis. The in-silico analysis suggested potential binding affinity of RT with TRAF-6 and BCL-2.

CONCLUSION

In brief RT inhibited AGE-induced inflammatory reaction and also degradation of ECM via targeting the NF-κB/MAPK pathway proteins BCL-2 and TRAF-6. RT can be a potential molecule in treating OA.

A unique esophageal extracellular matrix proteome alters normal fibroblast function in severe eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic TH2 disorder complicated by tissue fibrosis and loss of esophageal luminal patency. The fibrostenotic esophagus does not respond well to therapy, but profibrotic therapeutic targets are largely unclear.

OBJECTIVE

Our aim was to utilize proteomics and primary cells as a novel approach to determine relevant profibrotic factors.

METHODS

We utilized primary esophageal EoE and normal fibroblasts, their derivative extracellular matrixes (ECMs), an approach of fibroblast culture on autologous versus nonautologous ECM, and proteomics to elucidate EoE ECM proteins that dysregulate cellular function.

RESULTS

We cultured esophageal fibroblasts from normal esophagi and esophagi from patients with severe EoE on autologous versus nonautologous ECM. The EoE ECM proteome shifted normal esophageal fibroblast protein expression. Proteomic analysis demonstrated that thrombospondin-1 is detected only in the EoE ECM, is central in the EoE ECM protein-protein interactome, is found at significantly elevated levels in biopsy specimens from patients with active EoE, and induces fibroblast collagen I production.

CONCLUSION

Fibroblasts from patients with EoE secrete a unique ECM proteome that reflects their in vivo state and induces collagen I and α-smooth muscle actin protein expression from normal fibroblasts. Thrombospondin-1 is a previously unappreciated profibrotic molecule in EoE.

Targeting immunometabolism of neoplasms by interleukins: A promising immunotherapeutic strategy for cancer treatment

In recent years, tumor metabolism has become a prevalent research topic for scientists and pharmaceutical companies. As research in the field has progressed, the metabolism-based therapy of tumors has ushered in new opportunities. Most tumors emerge and evolve under selective pressure from their microenvironment, which promotes the diversification of both neoplastic and non-neoplastic compartments of the tumor microenvironment (TME), and finally reaches a certain degree of intratumoral heterogeneity. As a result of the tumor intratumoral heterogeneity, tumor cells often possess a complex energy metabolism phenotype. During tumor progression, the metabolism for both tumor parenchyma and stroma is reprogrammed. The tumor stroma mainly consists of the extracellular matrix, fibroblasts, and immune cells. Interestingly, tumor-infiltrating immune cells utilize different metabolites based on their subtype and function, and these immunometabolic pathways can be modified in the TME. In particular, interleukins play a vital role in the activation and differentiation of immune cells and have exhibited multiple effects on tumor cell neoplasia, invasion, and metastasis. In this review, we summarize the common mechanisms of interleukins affecting the tumor and tumor-infiltrating immune cells metabolically and discuss how these mechanisms may lead to novel therapeutic opportunities. This review might contribute to the novel development of cancer immunotherapy.

Immune Cell Modulation of the Extracellular Matrix Contributes to the Pathogenesis of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy with a five-year survival rate of only 9%. PDAC is characterized by a dense, fibrotic stroma composed of extracellular matrix (ECM) proteins. This desmoplastic stroma is a hallmark of PDAC, representing a significant physical barrier that is immunosuppressive and obstructs penetration of cytotoxic chemotherapy agents into the tumor microenvironment (TME). Additionally, dense ECM promotes hypoxia, making tumor cells refractive to radiation therapy and alters their metabolism, thereby supporting proliferation and survival. In this review, we outline the significant contribution of fibrosis to the pathogenesis of pancreatic cancer, with a focus on the cross talk between immune cells and pancreatic stellate cells that contribute to ECM deposition. We emphasize the cellular mechanisms by which neutrophils and macrophages, specifically, modulate the ECM in favor of PDAC-progression. Furthermore, we investigate how activated stellate cells and ECM influence immune cells and promote immunosuppression in PDAC. Finally, we summarize therapeutic strategies that target the stroma and hinder immune cell promotion of fibrogenesis, which have unfortunately led to mixed results. An enhanced understanding of the complex interactions between the pancreatic tumor ECM and immune cells may uncover novel treatment strategies that are desperately needed for this devastating disease.

Tumor Extracellular Matrix Stiffness Promptly Modulates the Phenotype and Gene Expression of Infiltrating T Lymphocytes

The immune system is a fine modulator of the tumor biology supporting or inhibiting its progression, growth, invasion and conveys the pharmacological treatment effect. Tumors, on their side, have developed escaping mechanisms from the immune system action ranging from the direct secretion of biochemical signals to an indirect reaction, in which the cellular actors of the tumor microenvironment (TME) collaborate to mechanically condition the extracellular matrix (ECM) making it inhospitable to immune cells. TME is composed of several cell lines besides cancer cells, including tumor-associated macrophages, cancer-associated fibroblasts, CD4+ and CD8+ lymphocytes, and innate immunity cells. These populations interface with each other to prepare a conservative response, capable of evading the defense mechanisms implemented by the host's immune system. The presence or absence, in particular, of cytotoxic CD8+ cells in the vicinity of the main tumor mass, is able to predict, respectively, the success or failure of drug therapy. Among various mechanisms of immunescaping, in this study, we characterized the modulation of the phenotypic profile of CD4+ and CD8+ cells in resting and activated states, in response to the mechanical pressure exerted by a three-dimensional in vitro system, able to recapitulate the rheological and stiffness properties of the tumor ECM.

Aspects of the Tumor Microenvironment Involved in Immune Resistance and Drug Resistance

The tumor microenvironment (TME) is a complex and ever-changing "rogue organ" composed of its own blood supply, lymphatic and nervous systems, stroma, immune cells and extracellular matrix (ECM). These complex components, utilizing both benign and malignant cells, nurture the harsh, immunosuppressive and nutrient-deficient environment necessary for tumor cell growth, proliferation and phenotypic flexibility and variation. An important aspect of the TME is cellular crosstalk and cell-to-ECM communication. This interaction induces the release of soluble factors responsible for immune evasion and ECM remodeling, which further contribute to therapy resistance. Other aspects are the presence of exosomes contributed by both malignant and benign cells, circulating deregulated microRNAs and TME-specific metabolic patterns which further potentiate the progression and/or resistance to therapy. In addition to biochemical signaling, specific TME characteristics such as the hypoxic environment, metabolic derangements, and abnormal mechanical forces have been implicated in the development of treatment resistance. In this review, we will provide an overview of tumor microenvironmental composition, structure, and features that influence immune suppression and contribute to treatment resistance.

Prognostic and therapeutic implications of extracellular matrix associated gene signature in renal clear cell carcinoma

Complex interactions in tumor microenvironment between ECM (extra-cellular matrix) and cancer cell plays a central role in the generation of tumor supportive microenvironment. In this study, the expression of ECM-related genes was explored for prognostic and immunological implication in clear cell renal clear cell carcinoma (ccRCC). Out of 964 ECM genes, higher expression (z-score > 2) of 35 genes showed significant association with overall survival (OS), progression-free survival (PFS) and disease-specific survival (DSS). On comparison to normal tissue, 12 genes (NUDT1, SIGLEC1, LRP1, LOXL2, SERPINE1, PLOD3, ZP3, RARRES2, TGM2, COL3A1, ANXA4, and POSTN) showed elevated expression in kidney tumor (n = 523) compared to normal (n = 100). Further, Cox proportional hazard model was utilized to develop 12 genes ECM signature that showed significant association with overall survival in TCGA dataset (HR = 2.45; 95% CI [1.78-3.38]; p < 0.01). This gene signature was further validated in 3 independent datasets from GEO database. Kaplan-Meier log-rank test significantly associated patients with elevated expression of this gene signature with a higher risk of mortality. Further, differential gene expression analysis using DESeq2 and principal component analysis (PCA) identified genes with the highest fold change forming distinct clusters between ECM-rich high-risk and ECM-poor low-risk patients. Geneset enrichment analysis (GSEA) identified significant perturbations in homeostatic kidney functions in the high-risk group. Further, higher infiltration of immunosuppressive T-reg and M2 macrophages was observed in high-risk group patients. The present study has identified a prognostic signature with associated tumor-promoting immune niche with clinical utility in ccRCC. Further exploration of ECM dynamics and validation of this gene signature can assist in design and application of novel therapeutic approaches.

Immunomodulatory Scaffolds Derived from Lymph Node Extracellular Matrices

Immunomodulation in the local tissue microenvironment is pivotal for the determination of macrophage phenotypes and regulation of functions necessary for pro-healing effects. Herein, we demonstrate that a lymph node extracellular matrix (LNEM) prepared by the decellularization of lymph node tissues can mimic lymph node microenvironments for immunomodulation in two-dimensional (2D) and three-dimensional (3D) formats. The LNEM exhibits strengthened immunomodulatory effects in comparison to conventional collagen-based platforms. A 3D LNEM hydrogel is more effective than the 2D LNEM coating in inducing M2 macrophage polarization. The 3D LNEM induces macrophage elongation and enhances the M2-type marker expression and the secretion of anti-inflammatory cytokines. Additionally, the phagocytic function of macrophages is improved upon exposure to the intricate 3D LNEM environment. We demonstrate the reduced susceptibility of liver organoids to a hepatotoxic drug when co-cultured with macrophages in a 3D LNEM. This effect could be attributed to the enhanced anti-inflammatory functions and indicates its potential as a drug-testing platform that enables drug responses similar to those observed in vivo. Finally, the implantation of an LNEM hydrogel in a mouse volumetric muscle loss model facilitates the recruitment of host macrophages to the site of injury and enhances macrophage polarization toward the M2 phenotype for tissue healing in vivo. Therefore, 3D immune system-mimicking biomaterials could serve as useful platforms for tissue modeling and regenerative medicine development.

Natural Killer Cell Integrins and Their Functions in Tissue Residency

Integrins are transmembrane receptors associated with adhesion and migration and are often highly differentially expressed receptors amongst natural killer cell subsets in microenvironments. Tissue resident natural killer cells are frequently defined by their differential integrin expression compared to other NK cell subsets, and integrins can further localize tissue resident NK cells to tissue microenvironments. As such, integrins play important roles in both the phenotypic and functional identity of NK cell subsets. Here we review the expression of integrin subtypes on NK cells and NK cell subsets with the goal of better understanding how integrin selection can dictate tissue residency and mediate function from the nanoscale to the tissue environment.

A murine model of Lyme disease demonstrates that Borrelia burgdorferi colonizes the dura mater and induces inflammation in the central nervous system

Lyme disease, which is caused by infection with Borrelia burgdorferi and related species, can lead to inflammatory pathologies affecting the joints, heart, and nervous systems including the central nervous system (CNS). Inbred laboratory mice have been used to define the kinetics of B. burgdorferi infection and host immune responses in joints and heart, however similar studies are lacking in the CNS of these animals. A tractable animal model for investigating host-Borrelia interactions in the CNS is key to understanding the mechanisms of CNS pathogenesis. Therefore, we characterized the kinetics of B. burgdorferi colonization and associated immune responses in the CNS of mice during early and subacute infection. Using fluorescence-immunohistochemistry, intravital microscopy, bacterial culture, and quantitative PCR, we found B. burgdorferi routinely colonized the dura mater of C3H mice, with peak spirochete burden at day 7 post-infection. Dura mater colonization was observed for several Lyme disease agents including B. burgdorferi, B. garinii, and B. mayonii. RNA-sequencing and quantitative RT-PCR showed that B. burgdorferi infection was associated with increased expression of inflammatory cytokines and a robust interferon (IFN) response in the dura mater. Histopathologic changes including leukocytic infiltrates and vascular changes were also observed in the meninges of infected animals. In contrast to the meninges, we did not detect B. burgdorferi, infiltrating leukocytes, or large-scale changes in cytokine profiles in the cerebral cortex or hippocampus during infection; however, both brain regions demonstrated similar changes in expression of IFN-stimulated genes as observed in peripheral tissues and meninges. Taken together, B. burgdorferi is capable of colonizing the meninges in laboratory mice, and induces localized inflammation similar to peripheral tissues. A sterile IFN response in the absence of B. burgdorferi or inflammatory cytokines is unique to the brain parenchyma, and provides insight into the potential mechanisms of CNS pathology associated with this important pathogen.

Modification of Extracellular Matrix Enhances Oncolytic Adenovirus Immunotherapy in Glioblastoma

PURPOSE

Extracellular matrix (ECM) component hyaluronan (HA) facilitates malignant phenotypes of glioblastoma (GBM), however, whether HA impacts response to GBM immunotherapies is not known. Herein, we investigated whether degradation of HA enhances oncolytic virus immunotherapy for GBM.

EXPERIMENTAL DESIGN

Presence of HA was examined in patient and murine GBM. Hyaluronidase-expressing oncolytic adenovirus, ICOVIR17, and its parental virus, ICOVIR15, without transgene, were tested to determine if they increased animal survival and modulated the immune tumor microenvironment (TME) in orthotopic GBM. HA regulation of NF-κB signaling was examined in virus-infected murine macrophages. We combined ICOVIR17 with PD-1 checkpoint blockade and assessed efficacy and determined mechanistic contributions of tumor-infiltrating myeloid and T cells.

RESULTS

Treatment of murine orthotopic GBM with ICOVIR17 increased tumor-infiltrating CD8+ T cells and macrophages, and upregulated PD-L1 on GBM cells and macrophages, leading to prolonged animal survival, compared with control virus ICOVIR15. High molecular weight HA inhibits adenovirus-induced NF-κB signaling in macrophages in vitro, linking HA degradation to macrophage activation. Combining ICOVIR17 with anti-PD-1 antibody further extended the survival of GBM-bearing mice, achieving long-term remission in some animals. Mechanistically, CD4+ T cells, CD8+ T cells, and macrophages all contributed to the combination therapy that induced tumor-associated proinflammatory macrophages and tumor-specific T-cell cytotoxicity locally and systemically.

CONCLUSIONS

Our studies are the first to show that immune modulatory ICOVIR17 has a dual role of mediating degradation of HA within GBM ECM and subsequently modifying the immune landscape of the TME, and offers a mechanistic combination immunotherapy with PD-L1/PD-1 blockade that remodels innate and adaptive immune cells.

Juvenile, but Not Adult, Mice Display Increased Myeloid Recruitment and Extracellular Matrix Remodeling during Respiratory Syncytial Virus Infection

Early life respiratory syncytial virus (RSV) infection has been linked to the onset of asthma. Despite this association, our knowledge of the progression of the initial viral infection is limited, and no safe or effective vaccine currently exists. Bronchioalveolar lavage, whole-lung cellular isolation, and gene expression analysis were performed on 3-wk- (juvenile) and 8-wk-old (adult) RSV-infected C57BL/6 mice to investigate age-related differences in immunologic responses; juvenile mice displayed a sustained myeloid infiltrate (including monocytes and neutrophils) with increased RNA expression of Ccl2, Ccl3, and Ccl4, when compared with adult mice, at 72 h postinfection. Juvenile mice demonstrated αSma expression (indicative of myofibroblast activity), increased hyaluronan deposition in the lung parenchyma (attributed to asthma progression), and a lack of CD64 upregulation on the surface of monocytes (which, in conjunction with serum amyloid P, is responsible for clearing residual hyaluronan and cellular debris). RSV infection of human airway epithelial cell, human lung fibroblast, and U937 monocyte cocultures (at air-liquid interface) displayed similar CCL expression and suggested matrix metalloproteinase-7 and MMP9 as possible extracellular matrix modifiers. These mouse data, in conjunction with our findings in human monocytes, suggest that the sustained influx of myeloid cells in the lungs of juvenile mice during acute RSV infection could potentiate extracellular matrix remodeling, facilitating conditions that support the development of asthma.

Immunomodulatory Role of the Extracellular Matrix Within the Liver Disease Microenvironment

Chronic liver disease when accompanied by underlying fibrosis, is characterized by an accumulation of extracellular matrix (ECM) proteins and chronic inflammation. Although traditionally considered as a passive and largely architectural structure, the ECM is now being recognized as a source of potent damage-associated molecular pattern (DAMP)s with immune-active peptides and domains. In parallel, the ECM anchors a range of cytokines, chemokines and growth factors, all of which are capable of modulating immune responses. A growing body of evidence shows that ECM proteins themselves are capable of modulating immunity either directly via ligation with immune cell receptors including integrins and TLRs, or indirectly through release of immunoactive molecules such as cytokines which are stored within the ECM structure. Notably, ECM deposition and remodeling during injury and fibrosis can result in release or formation of ECM-DAMPs within the tissue, which can promote local inflammatory immune response and chemotactic immune cell recruitment and inflammation. It is well described that the ECM and immune response are interlinked and mutually participate in driving fibrosis, although their precise interactions in the context of chronic liver disease are poorly understood. This review aims to describe the known pro-/anti-inflammatory and fibrogenic properties of ECM proteins and DAMPs, with particular reference to the immunomodulatory properties of the ECM in the context of chronic liver disease. Finally, we discuss the importance of developing novel biotechnological platforms based on decellularized ECM-scaffolds, which provide opportunities to directly explore liver ECM-immune cell interactions in greater detail.

Innate Immunity Effector Cells as Inflammatory Drivers of Cardiac Fibrosis

Despite relevant advances made in therapies for cardiovascular diseases (CVDs), they still represent the first cause of death worldwide. Cardiac fibrosis and excessive extracellular matrix (ECM) remodeling are common end-organ features in diseased hearts, leading to tissue stiffness, impaired myocardial functional, and progression to heart failure. Although fibrosis has been largely recognized to accompany and complicate various CVDs, events and mechanisms driving and governing fibrosis are still not entirely elucidated, and clinical interventions targeting cardiac fibrosis are not yet available. Immune cell types, both from innate and adaptive immunity, are involved not just in the classical response to pathogens, but they take an active part in “sterile” inflammation, in response to ischemia and other forms of injury. In this context, different cell types infiltrate the injured heart and release distinct pro-inflammatory cytokines that initiate the fibrotic response by triggering myofibroblast activation. The complex interplay between immune cells, fibroblasts, and other non-immune/host-derived cells is now considered as the major driving force of cardiac fibrosis. Here, we review and discuss the contribution of inflammatory cells of innate immunity, including neutrophils, macrophages, natural killer cells, eosinophils and mast cells, in modulating the myocardial microenvironment, by orchestrating the fibrogenic process in response to tissue injury. A better understanding of the time frame, sequences of events during immune cells infiltration, and their action in the injured inflammatory heart environment, may provide a rationale to design new and more efficacious therapeutic interventions to reduce cardiac fibrosis.

Vitamin C: A stem cell promoter in cancer metastasis and immunotherapy

Vitamin C is an electron donor and is involved in a variety of biochemical reactions in stem cell and cancer stem cell, as well as collagen synthesis and the regulation of hypoxia-inducible factor synthesis, which two affect extracellular matrix remodelling and hence cancer metastasis. Specific doses of vitamin C can stop cancer cell glycolysis and block nitroso synthesis, indicating the potential of vitamin C in cancer treatment. Recent studies preliminary revealed Vitamin C enhance the cancer's immune response to anti PD-L1 therapy through multiple indirect approaches. Herein we reviewed the recent function of vitamin C for further research in sequential aspects of cancer stem cell, extracellular matrix remodeling, cancer metastasis and cancer immunotherapy.

Stromal regulation of tumor-associated lymphatics

Recent advances have identified a growing array of roles played by lymphatics in the tumor microenvironment, from providing a route of metastasis to immune modulation. The tumor microenvironment represents an exceptionally complex, dynamic niche comprised of a diverse mixture of cancer cells and normal host cells termed the stroma. This review discusses our current understanding of stromal elements and how they regulate lymphatic growth and functional properties in the tumor context.

CD4+ T Cell Interstitial Migration Controlled by Fibronectin in the Inflamed Skin

The extracellular matrix (ECM) is extensively remodeled during inflammation providing essential guidance cues for immune cell migration and signals for cell activation and survival. There is increasing interest in the therapeutic targeting of ECM to mitigate chronic inflammatory diseases and enhance access to the tumor microenvironment. T cells utilize the ECM as a scaffold for interstitial migration, dependent on T cell expression of matrix-binding integrins αVβ1/αVβ3 and tissue display of the respective RGD-containing ligands. The specific ECM components that control T cell migration are unclear. Fibronectin (FN), a canonical RGD-containing matrix component, is heavily upregulated in inflamed tissues and in vitro can serve as a substrate for leukocyte migration. However, limited by lack of tools to intravitally visualize and manipulate FN, the specific role of FN in effector T cell migration in vivo is unknown. Here, we utilize fluorescently-tagged FN to probe for FN deposition, and intravital multiphoton microscopy to visualize T cell migration relative to FN in the inflamed ear dermis. Th1 cells were found to migrate along FN fibers, with T cells appearing to actively push or pull against flexible FN fibers. To determine the importance of T cell interactions with FN, we used a specific inhibitor of FN polymerization, pUR4. Intradermal delivery of pUR4 (but not the control peptide) to the inflamed skin resulted in a local reduction in FN deposition. We also saw a striking attenuation of Th1 effector T cell movement at the pUR4 injection site, suggesting FN plays a key role in T cell interstitial migration. In mechanistic studies, pUR4 incubation with FN in vitro resulted in enhanced tethering of T cells to FN matrix, limiting productive migration. In vivo, such tethering led to increased Th1 accumulation in the inflamed dermis. Enhanced Th1 accumulation exacerbated inflammation with increased Th1 activation and IFNγ cytokine production. Thus, our studies highlight the importance of ECM FN fibrils for T cell migration in inflamed tissues and suggest that manipulating local levels of ECM FN may prove beneficial in promoting T cell accumulation in tissues and enhancing local immunity to infection or cancer.

Gene silencing of extracellular matrix protein 1 (ECM1) results in phenotypic alterations of dermal fibroblasts reminiscent of clinical features of lichen sclerosus

BACKGROUND

Lichen sclerosus (LS) is an acquired inflammatory mucocutaneous disease affecting the anogenital area, characterized histologically by hyalinosis and thickened vessel walls in the dermis. The presence of serum autoantibodies against extracellular matrix protein 1 (ECM1) in LS patients may suggest its involvement in disease pathogenesis.

OBJECTIVE

To examine if reduced ECM1 production by dermal fibroblasts contributes to the pathogenic features of LS.

METHODS

Gene expression in ECM1 knockdown human dermal fibroblasts was analyzed by cDNA microarray. Functional enrichment for genes involved in cellular functions was conducted. Protein expression was analyzed by ELISA and confocal laser scanning microscopy using LS skin.

RESULTS

Microarray analysis identified 3035 differentially expressed genes in ECM1 knockdown cells, wherein 1471 were upregulated genes related exclusively to cell adhesion, proliferation, apoptosis, intracellular signaling, and extracellular matrix organization. Further narrowing with criteria specific for localization and function of ECM1 identified 48 upregulated genes identified to have structural, fibrogenic, and carcinogenic properties. Of these, laminin-332 and collagen-IV displayed altered immunolabeling within the basement membrane zone (BMZ) and dermal vessels in LS skin, similar to that of collagen-VII, which exhibited unchanged transcription levels in ECM1-knockdown fibroblasts. Collagen-VII bound to recombinant ECM1 in a solid-phase immunoassay and colocalized with ECM1 in the skin BMZ. Further, ECM1-knockdown fibroblasts exhibited a marked delay in cell migration and gel contraction.

CONCLUSION

In the absence of ECM1 expression in fibroblasts there is selective dysregulation and disassembly of structural and extracellular matrix molecules, which may result in microstructural abnormalities reminiscent of LS.

Crosstalk between Neospora caninum and the bovine host at the maternal-foetal interface determines the outcome of infection

Neospora caninum is an apicomplexan cyst-forming parasite that is considered one of the main causes of abortion. The pathogenic mechanisms associated with parasite virulence at the maternal-foetal interface that are responsible for the outcome of infection are largely unknown. Here, utilizing placentomes from cattle experimentally infected with high-virulence (Nc-Spain7) and low-virulence (Nc-Spain1H) isolates, we studied key elements of the innate and adaptive immune responses, as well as components of the extracellular matrix (ECM), at 10 and 20 days post-infection (dpi). The low-virulence isolate elicited a robust immune response characterized by upregulation of genes involved in pathogen recognition, chemokines and pro-inflammatory cytokines, crucial for its adequate control. In addition, Nc-Spain1H triggered the expression of anti-inflammatory cytokines and other mechanisms implicated in the maintenance of ECM integrity to ensure foetal survival. In contrast, local immune responses were initially (10 dpi) impaired by Nc-Spain7, allowing parasite multiplication. Subsequently (20 dpi), a predominantly pro-inflammatory Th1-based response and an increase in leucocyte infiltration were observed. Moreover, Nc-Spain7-infected placentomes from animals carrying non-viable foetuses exhibited higher expression of the IL-8, TNF-α, iNOS and SERP-1 genes and lower expression of the metalloproteases and their inhibitors than Nc-Spain7-infected placentomes from animals carrying viable foetuses. In addition, profound placental damage characterized by an alteration in the ECM organization in necrotic foci, which could contribute to foetal death, was found. Two different host-parasite interaction patterns were observed at the bovine placenta as representative examples of different evolutionary strategies used by this parasite for transmission to offspring.

CAR-T Cells Hit the Tumor Microenvironment: Strategies to Overcome Tumor Escape

Chimeric antigen receptor (CAR) T cell therapies have demonstrated remarkable efficacy for the treatment of hematological malignancies. However, in patients with solid tumors, objective responses to CAR-T cell therapy remain sporadic and transient. A major obstacle for CAR-T cells is the intrinsic ability of tumors to evade immune responses. Advanced solid tumors are largely composed of desmoplastic stroma and immunosuppressive modulators, and characterized by aberrant cell proliferation and vascularization, resulting in hypoxia and altered nutrient availability. To mount a curative response after infusion, CAR-T cells must infiltrate the tumor, recognize their cognate antigen and perform their effector function in this hostile tumor microenvironment, to then differentiate and persist as memory T cells that confer long-term protection. Fortunately, recent advances in synthetic biology provide a wide set of tools to genetically modify CAR-T cells to overcome some of these obstacles. In this review, we provide a comprehensive overview of the key tumor intrinsic mechanisms that prevent an effective CAR-T cell antitumor response and we discuss the most promising strategies to prevent tumor escape to CAR-T cell therapy.

Macphatics and PoEMs in Postpartum Mammary Development and Tumor Progression

Postpartum mammary gland involution is a mammalian tissue remodeling event that occurs after pregnancy and lactation to return the gland to the pre-pregnant state. This event is characterized by apoptosis and lysosomal-mediated cell death of the majority of the lactational mammary epithelium, followed by remodeling of the extracellular matrix, influx of immune cell populations (in particular, T helper cells, monocytes, and macrophages), and neo-lymphangiogenesis. This postpartum environment has been shown to be promotional for tumor growth and metastases and may partially account for why women diagnosed with breast cancer during the postpartum period or within 5 years of last childbirth have an increased risk of developing metastases when compared to their nulliparous counterparts. The lymphatics and macrophages present during mammary gland involution have been implicated in promoting the observed growth and metastasis. Of importance are the macrophages, which are of the "M2" phenotype and are known to create a pro-tumor microenvironment. In this report, we describe a subset of postpartum macrophages that express lymphatic proteins (PoEMs) and directly interact with lymphatic vessels to form chimeric vessels or "macphatics". Additionally, these PoEMs are very similar to tumor-associated macrophages that also express lymphatic proteins and are present at the sites of lymphatic vessels where tumors escape the tissue and enter the lymphatic vasculature. Further characterizing these PoEMs may offer insight in preventing lymphatic metastasis of breast cancer, as well as provide information for how developmental programming of lymphatic endothelial cells and macrophages can contribute to different disease progression.

In utero estrogenic endocrine disruption alters the stroma to increase extracellular matrix density and mammary gland stiffness

BACKGROUND

In utero endocrine disruption is linked to increased risk of breast cancer later in life. Despite numerous studies establishing this linkage, the long-term molecular changes that predispose mammary cells to carcinogenic transformation are unknown. Herein, we investigated how endocrine disrupting compounds (EDCs) drive changes within the stroma that can contribute to breast cancer susceptibility.

METHODS

We utilized bisphenol A (BPA) as a model of estrogenic endocrine disruption to analyze the long-term consequences in the stroma. Deregulated genes were identified by RNA-seq transcriptional profiling of adult primary fibroblasts, isolated from female mice exposed to in utero BPA. Collagen staining, collagen imaging techniques, and permeability assays were used to characterize changes to the extracellular matrix. Finally, gland stiffness tests were performed on exposed and control mammary glands.

RESULTS

We identified significant transcriptional deregulation of adult fibroblasts exposed to in utero BPA. Deregulated genes were associated with cancer pathways and specifically extracellular matrix composition. Multiple collagen genes were more highly expressed in the BPA-exposed fibroblasts resulting in increased collagen deposition in the adult mammary gland. This transcriptional reprogramming of BPA-exposed fibroblasts generates a less permeable extracellular matrix and a stiffer mammary gland. These phenotypes were only observed in adult 12-week-old, but not 4-week-old, mice. Additionally, diethylstilbestrol, known to increase breast cancer risk in humans, also increases gland stiffness similar to BPA, while bisphenol S does not.

CONCLUSIONS

As breast stiffness, extracellular matrix density, and collagen deposition have been directly linked to breast cancer risk, these data mechanistically connect EDC exposures to molecular alterations associated with increased disease susceptibility. These alterations develop over time and thus contribute to cancer risk in adulthood.

Versican-A Critical Extracellular Matrix Regulator of Immunity and Inflammation

The extracellular matrix (ECM) proteoglycan, versican increases along with other ECM versican binding molecules such as hyaluronan, tumor necrosis factor stimulated gene-6 (TSG-6), and inter alpha trypsin inhibitor (IαI) during inflammation in a number of different diseases such as cardiovascular and lung disease, autoimmune diseases, and several different cancers. These interactions form stable scaffolds which can act as "landing strips" for inflammatory cells as they invade tissue from the circulation. The increase in versican is often coincident with the invasion of leukocytes early in the inflammatory process. Versican interacts with inflammatory cells either indirectly via hyaluronan or directly via receptors such as CD44, P-selectin glycoprotein ligand-1 (PSGL-1), and toll-like receptors (TLRs) present on the surface of immune and non-immune cells. These interactions activate signaling pathways that promote the synthesis and secretion of inflammatory cytokines such as TNFα, IL-6, and NFκB. Versican also influences inflammation by interacting with a variety of growth factors and cytokines involved in regulating inflammation thereby influencing their bioavailability and bioactivity. Versican is produced by multiple cell types involved in the inflammatory process. Conditional total knockout of versican in a mouse model of lung inflammation demonstrated significant reduction in leukocyte invasion into the lung and reduced inflammatory cytokine expression. While versican produced by stromal cells tends to be pro-inflammatory, versican expressed by myeloid cells can create anti-inflammatory and immunosuppressive microenvironments. Inflammation in the tumor microenvironment often contains elevated levels of versican. Perturbing the accumulation of versican in tumors can inhibit inflammation and tumor progression in some cancers. Thus versican, as a component of the ECM impacts immunity and inflammation through regulating immune cell trafficking and activation. Versican is emerging as a potential target in the control of inflammation in a number of different diseases.

Hyaluronan Fragmentation During Inflammatory Pathologies: A Signal that Empowers Tissue Damage

The mechanisms that modulate the response to tissue injury are not fully understood. Abnormalities in the repair response are associated with a variety of chronic disease states characterized by inflammation, followed subsequently by excessive ECM deposition. As cell-matrix interactions are able to regulate cellular homeostasis, modification of ECM integrity appears to be an unspecific factor in promoting the onset and progression of inflammatory diseases. Evidence is emerging to show that endogenous ECM molecules supply signals to damage tissues and cells in order to promote further ECM degradation and inflammation progression. Several investigations have been confirmed that HA fragments of different molecular sizes exhibit different biological effects and responses. In fact, the increased deposition of HA into the ECM is a strong hallmark of inflammation processes. In the context of inflammatory pathologies, highly polymerized HA is broken down into small components, which are able to exacerbate the inflammatory response by inducing the release of various detrimental mediators such as reactive oxygen species, cytokines, chemokines and destructive enzymes and by facilitating the recruitment of leukocytes. However, strategies involving the modulation of the HA fragment with specific receptors on cell surface could represent different promising effects for therapeutic scope. This review will focus on the inflammation action of small HA fragments in recent years obtained by in vivo reports.

Fibroblastic Reticular Cells Control Conduit Matrix Deposition during Lymph Node Expansion

Lymph nodes (LNs) act as filters, constantly sampling peripheral cues. This is facilitated by the conduit network, a tubular structure of aligned extracellular matrix (ECM) fibrils ensheathed by fibroblastic reticular cells (FRCs). LNs undergo rapid 3- to 5-fold expansion during adaptive immune responses, but these ECM-rich structures are not permanently damaged. Whether conduit flow or filtering function is affected during LN expansion is unknown. Here, we show that conduits are partially disrupted during acute LN expansion, but FRC-FRC contacts remain connected. We reveal that polarized FRCs deposit ECM basolaterally using LL5-β and that ECM production is regulated at transcriptional and secretory levels by the C-type lectin CLEC-2, expressed by dendritic cells. Inflamed LNs maintain conduit size exclusion, and flow is disrupted but persists, indicating the robustness of this structure despite rapid tissue expansion. We show how dynamic communication between peripheral tissues and LNs provides a mechanism to prevent inflammation-induced fibrosis in lymphoid tissue.

Extracellular matrix turnover and inflammation in chemically-induced TMJ arthritis mouse models

The temporomandibular joint (TMJ) is a fibrocartilaginous tissue critical for chewing and speaking. In patients with temporomandibular disorders (TMDs), permanent tissue loss can occur. Recapitulating the complexity of TMDs in animal models is difficult, yet critical for the advent of new therapies. Synovial fluid from diseased human samples revealed elevated levels of tumor necrosis factor alpha (TNF-alpha). Here, we propose to recapitulate these findings in mice by subjecting murine TMJs with TNF-alpha or CFA (Complete Freund’s Adjuvant) in mandibular condyle explant cultures and by local delivery in vivo using TMJ intra-articular injections. Both TNF-alpha and CFA delivery to whole mandibular explants and in vivo increased extracellular matrix deposition and increased cartilage thickness, while TNF-alpha treated explants had increased expression of inflammatory cytokines and degradative enzymes. Moreover, the application of TNF-alpha or CFA in both models reduced cell number. CFA delivery in vivo caused soft tissue inflammation, including pannus formation. Our work provides two methods of chemically induced TMJ inflammatory arthritis through a condyle explant model and intra-articular injection model that replicate findings seen in synovial fluid of human patients, which can be used for further studies delineating the mechanisms underlying TMJ pathology.

Ex vivo physiological compression of human osteoarthritis cartilage modulates cellular and matrix components

Mechanical stimulation appears to play a key role in cartilage homeostasis maintenance, but it can also contribute to osteoarthritis (OA) pathogenesis. Accumulating evidence suggests that cartilage loading in the physiological range contributes to tissue integrity maintenance, whereas excessive or reduced loading have catabolic effects. However, how mechanical stimuli can regulate joint homeostasis is still not completely elucidated and few data are available on human cartilage. We aimed at investigating human OA cartilage response to ex vivo loading at physiological intensity. Cartilage explants from ten OA patients were subjected to ex vivo controlled compression, then recovered and used for gene and protein expression analysis of cartilage homeostasis markers. Compressed samples were compared to uncompressed ones in presence or without interleukin 1β (IL-1β) or interleukin 4 (IL-4). Cartilage explants compressed in combination with IL-4 treatment showed the best histological scores. Mechanical stimulation was able to significantly modify the expression of collagen type II (collagen 2), aggrecan, SOX9 transcription factor, cartilage oligomeric matrix protein (COMP), collagen degradation marker C2C and vascular endothelial growth factor (VEGF). Conversely, ADAMTS4 metallopeptidase, interleukin 4 receptor alpha (IL4Rα), chondroitin sulfate 846 epitope (CS846), procollagen type 2 C-propeptide (CPII) and glycosaminoglycans (GAG) appeared not modulated. Our data suggest that physiological compression of OA human cartilage modulates the inflammatory milieu by differently affecting the expression of components and homeostasis regulators of the cartilage extracellular matrix.

Renal Inflammation and Fibrosis: A Double-edged Sword

Renal tissue injury initiates inflammatory and fibrotic processes that occur to promote regeneration and repair. After renal injury, damaged tissue releases cytokines and chemokines, which stimulate activation and infiltration of inflammatory cells to the kidney. Normal tissue repair processes occur simultaneously with activation of myofibroblasts, collagen deposition, and wound healing responses; however, prolonged activation of pro-inflammatory and pro-fibrotic cell types causes excess extracellular matrix deposition. This review focuses on the physiological and pathophysiological roles of specialized cell types, cytokines/chemokines, and growth factors, and their implications in recovery or exacerbation of acute kidney injury.

Pulmonary environmental cues drive group 2 innate lymphoid cell dynamics in mice and humans

Group 2 innate lymphoid cells (ILC2s) are enriched in mucosal tissues (e.g., lung) and respond to epithelial cell-derived cytokines initiating type 2 inflammation. During inflammation, ILC2 numbers are increased in the lung. However, the mechanisms controlling ILC2 trafficking and motility within inflamed lungs remain unclear and are crucial for understanding ILC2 function in pulmonary immunity. Using several approaches, including lung intravital microscopy, we demonstrate that pulmonary ILC2s are highly dynamic, exhibit amoeboid-like movement, and aggregate in the lung peribronchial and perivascular spaces. They express distinct chemokine receptors, including CCR8, and actively home to CCL8 deposits located around the airway epithelium. Within lung tissue, ILC2s were particularly motile in extracellular matrix-enriched regions. We show that collagen-I drives ILC2 to markedly change their morphology by remodeling their actin cytoskeleton to promote environmental exploration critical for regulating eosinophilic inflammation. Our study provides previously unappreciated insights into ILC2 migratory patterns during inflammation and highlights the importance of environmental guidance cues in the lung in controlling ILC2 dynamics.

MDSCs: Key Criminals of Tumor Pre-metastatic Niche Formation

The emergence of disseminated metastases remains the primary cause of mortality in cancer patients. Formation of the pre-metastatic niche (PMN), which precedes the establishment of tumor lesions, is critical for metastases. Bone marrow-derived myeloid cells (BMDCs) are indispensable for PMN formation. Myeloid-derived suppressor cells (MDSCs) are a population of immature myeloid cells that accumulate in patients with cancer and appear in the early PMN. The mechanisms by which MDSCs establish the pre-metastatic microenvironment in distant organs are largely unknown, although MDSCs play an essential role in metastasis. Here, we summarize the key factors associated with the recruitment and activation of MDSCs in the PMN and review the mechanisms by which MDSCs regulate PMN formation and evolution. Finally, we predict the potential value of MDSCs in PMN detection and therapy.

Macrophage and Fibroblast Interactions in Biomaterial-Mediated Fibrosis

Biomaterial-mediated inflammation and fibrosis remain a prominent challenge in designing materials to support tissue repair and regeneration. Despite the many biomaterial technologies that have been designed to evade or suppress inflammation (i.e., delivery of anti-inflammatory drugs, hydrophobic coatings, etc.), many materials are still subject to a foreign body response, resulting in encapsulation of dense, scar-like extracellular matrix. The primary cells involved in biomaterial-mediated fibrosis are macrophages, which modulate inflammation, and fibroblasts, which primarily lay down new extracellular matrix. While macrophages and fibroblasts are implicated in driving biomaterial-mediated fibrosis, the signaling pathways and spatiotemporal crosstalk between these cell types remain loosely defined. In this review, the role of M1 and M2 macrophages (and soluble cues) involved in the fibrous encapsulation of biomaterials in vivo is investigated, with additional focus on fibroblast and macrophage crosstalk in vitro along with in vitro models to study the foreign body response. Lastly, several strategies that have been used to specifically modulate macrophage and fibroblast behavior in vitro and in vivo to control biomaterial-mediated fibrosis are highlighted.

Production and characterization of monoclonal antibodies against recombinant extracellular domain of CD99

BACKGROUND AND OBJECTIVE

CD99/MIC2 gene product is a heavily glycosylated transmembrane protein which plays a major role in homotypic cell adhesion, apoptosis of double positive T cells and vesicular protein trafficking. It is over expressed in various cancers and has been considered as an ideal therapeutic target. The present study focused at developing monoclonal antibodies against the extracellular domain (ECD) of CD99 using hybridoma technology.

MATERIALS AND METHODS

In order to generate monoclonal antibodies, the recombinant ECD of CD99 was used for immunizing the mice. Resulting hybridomas were screened through indirect ELISA. Clones which gave high absorbance values were sub cloned by limiting dilution followed by isotype determination, IP, WB and FACS. The monoclonal antibody 547F2 4F12 was purified from culture supernatant using FPLC and further screened using IF. Finally, the antibodies were validated for specificity using siRNA knock-down.

RESULTS

We were able to establish stable hybridoma clones secreting CD99 antibodies. The antibodies reacted with both the recombinant ECD as well as the wild type CD99 and their isotype's were determined as IgM.

CONCLUSION

Based on these results, we propose that the purified monoclonal antibody 547F2 4F12 could be possibly used for targeting tumors which over express CD99.

High-Throughput Microfluidic 3D Cytotoxicity Assay for Cancer Immunotherapy (CACI-IMPACT Platform)

Adoptive cell transfer against solid tumors faces challenges to overcome tumor microenvironment (TME), which plays as a physical barrier and provides immuno-suppressive conditions. Classical cytotoxicity assays are widely used to measure killing ability of the engineered cytotoxic lymphocytes as therapeutics, but the results cannot represent the performance in clinical application due to the absence of the TME. This paper describes a 3D cytotoxicity assay using an injection molded plastic array culture (CACI-IMPACT) device for 3D cytotoxicity assay to assess killing abilities of cytotoxic lymphocytes in 3D microenvironment through a spatiotemporal analysis of the lymphocytes and cancer cells embedded in 3D extra cellular matrix (ECM). Rail-based microfluidic design was integrated within a single 96-well and the wells were rectangularly arrayed in 2 × 6 to enhance the experimental throughput. The rail-based microstructures facilitate hydrogel patterning with simple pipetting so that hydrogel pre-solution aspirated with 10 μl pipette can be patterned in 10 wells within 30 s. To demonstrate 3D cytotoxicity assay, we patterned HeLa cells encapsulated by collagen gel and observed infiltration, migration and cytotoxic activity of NK-92 cells against HeLa cells in the collagen matrix. We found that 3D ECM significantly reduced migration of cytotoxic lymphocytes and access to cancer cells, resulting in lower cytotoxicity compared with 2D assays. In dense ECM, the physical barrier function of the 3D matrix was enhanced, but the cytotoxic lymphocytes effectively killed cancer cells once they contacted with cancer cells. The results implied ECM significantly influences migration and cytotoxicity of cytotoxic lymphocytes. Hence, the CACI-IMPACT platform, enabling high-throughput 3D co-culture of cytotoxic lymphocyte with cancer cells, has the potential to be used for pre-clinical evaluation of cytotoxic lymphocytes engineered for immunotherapy against solid tumors.

Personalized Hydrogels for Engineering Diverse Fully Autologous Tissue Implants

Despite incremental improvements in the field of tissue engineering, no technology is currently available for producing completely autologous implants where both the cells and the scaffolding material are generated from the patient, and thus do not provoke an immune response that may lead to implant rejection. Here, a new approach is introduced to efficiently engineer any tissue type, which its differentiation cues are known, from one small tissue biopsy. Pieces of omental tissues are extracted from patients and, while the cells are reprogrammed to become induced pluripotent stem cells, the extracellular matrix is processed into an immunologically matching, thermoresponsive hydrogel. Efficient cell differentiation within a large 3D hydrogel is reported, and, as a proof of concept, the generation of functional cardiac, cortical, spinal cord, and adipogenic tissue implants is demonstrated. This versatile bioengineering approach may assist to regenerate any tissue and organ with a minimal risk for immune rejection.

A complex interplay between the extracellular matrix and the innate immune response to microbial pathogens

The role of the host extracellular matrix (ECM) in infection tends to be neglected. However, the complex interactions between invading pathogens, host tissues and immune cells occur in the context of the ECM. On the pathogen side, a variety of surface and secreted molecules, including microbial surface components recognizing adhesive matrix molecules and tissue-degrading enzymes, are employed that interact with different ECM proteins to effectively establish an infection at specific sites. Microbial pathogens can also hijack or misuse host proteolytic systems to modify the ECM, evade immune responses or process biologically active molecules such as cell surface receptors and cytokines that direct cell behaviour and immune defence. On the host side, the ECM composition and three-dimensional ultrastructure undergo significant modifications, which have a profound impact on the specific signals that the ECM conveys to immune cells at the forefront of infection. Unexpectedly, activated immune cells participate in the remodelling of the local ECM by synthesizing ECM glycoproteins, proteoglycans and collagen molecules. The close interplay between the ECM and the innate immune response to microbial pathogens ultimately affects the outcome of infection. This review explores and discusses recent data that implicate an active role for the ECM in the immune response to infection, encompassing antimicrobial activities, microbial recognition, macrophage activation, phagocytosis, leucocyte population balance, and transcriptional and post-transcriptional regulation of inflammatory networks, and may foster novel antimicrobial approaches.

Gene expression profiling identifies distinct molecular signatures in thrombotic and obstetric antiphospholipid syndrome

Antiphospholipid antibodies (aPL) cause vascular thrombosis (VT) and/or pregnancy morbidity (PM). Differential mechanisms however, underlying the pathogenesis of these different manifestations of antiphospholipid syndrome (APS) are not fully understood. Therefore, we compared the effects of aPL from patients with thrombotic or obstetric APS on monocytes to identify different molecular pathways involved in the pathogenesis of APS subtypes. VT or PM IgG induced similar numbers of differentially expressed (DE) genes in monocytes. However, gene ontology (GO) analysis of DE genes revealed disease-specific genome signatures. Compared to PM, VT-IgG showed specific up regulation of genes associated with cell response to stress, regulation of MAPK signalling pathway and cell communication. In contrast, PM-IgG regulated genes involved in cell adhesion, extracellular matrix and embryonic and skeletal development. A novel gene expression analysis based on differential variability (DV) was also applied. This analysis identified similar GO categories compared to DE analysis but also uncovered novel pathways modulated solely by PM or VT-IgG. Gene expression analysis distinguished a differential effect of VT or PM-IgG upon monocytes supporting the hypothesis that they trigger distinctive physiological mechanisms. This finding contributes to our understanding of the pathology of APS and may lead to the development of different targeted therapies for VT or PM APS.

Production of Elastin-Derived Peptides Contributes to the Development of Nonalcoholic Steatohepatitis

Affecting more than 30% of the Western population, nonalcoholic fatty liver disease (NAFLD) is the most common liver disease and can lead to multiple complications, including nonalcoholic steatohepatitis (NASH), cancer, hypertension, and atherosclerosis. Insulin resistance and obesity are described as potential causes of NAFLD. However, we surmised that factors such as extracellular matrix remodeling of large blood vessels, skin, or lungs may also participate in the progression of liver diseases. We studied the effects of elastin-derived peptides (EDPs), biomarkers of aging, on NAFLD progression. We evaluated the consequences of EDP accumulation in mice and of elastin receptor complex (ERC) activation on lipid storage in hepatocytes, inflammation, and fibrosis development. The accumulation of EDPs induces hepatic lipogenesis (i.e., SREBP1c and ACC), inflammation (i.e., Kupffer cells, IL-1β, and TGF-β), and fibrosis (collagen and elastin expression). These effects are induced by inhibition of the LKB1-AMPK pathway by ERC activation. In addition, pharmacological inhibitors of EDPs demonstrate that this EDP-driven lipogenesis and fibrosis relies on engagement of the ERC. Our data reveal a major role of EDPs in the development of NASH, and they provide new clues for understanding the relationship between NAFLD and vascular aging.

[Progress on cancer associated fibroblasts in tumor immunoregulation]

Cancer associated fibroblasts (CAFs) are important components of the tumor microenvironment. Through secreting of multiple growth factors, cytokines and proteases, CAFs play a significant role in regulating the recruitment and function of various innate immune cells and adaptive immune cells in tumor microenvironment. In addition, extracellular matrix secreted by CAFs can also promote the formation of immunosuppression and hypoxia of tumor microenvironment. Here, we review the progress on CAFs in regulation of immune cells and tumor immunity.

Fibroblasts in the Tumor Microenvironment: Shield or Spear?

Tumorigenesis is a complex process involving dynamic interactions between malignant cells and their surrounding stroma, including both the cellular and acellular components. Within the stroma, fibroblasts represent not only a predominant cell type, but also a major source of the acellular tissue microenvironment comprising the extracellular matrix (ECM) and soluble factors. Normal fibroblasts can exert diverse suppressive functions against cancer initiating and metastatic cells via direct cell-cell contact, paracrine signaling by soluble factors, and ECM integrity. The loss of such suppressive functions is an inherent step in tumor progression. A tumor cell-induced switch of normal fibroblasts into cancer-associated fibroblasts (CAFs), in turn, triggers a range of pro-tumorigenic signals accompanied by distraction of the normal tissue architecture, thus creating an optimal niche for cancer cells to grow extensively. To further support tumor progression and metastasis, CAFs secrete factors such as ECM remodeling enzymes that further modify the tumor microenvironment in combination with the altered adhesive forces and cell-cell interactions. These paradoxical tumor suppressive and promoting actions of fibroblasts are the focus of this review, highlighting the heterogenic molecular properties of both normal and cancer-associated fibroblasts, as well as their main mechanisms of action, including the emerging impact on immunomodulation and different therapy responses.

Morphophysiological changes in the splenic extracellular matrix of Leishmania infantum-naturally infected dogs is associated with alterations in lymphoid niches and the CD4+ T cell frequency in spleens

The spleen is one of the main affected organs in canine visceral leishmaniasis (CVL). Disorganization of the splenic white pulp (SWP) has been associated with immunosuppression and disease progression. This study aims to assess structural and cellular changes in the splenic extracellular matrix of dogs with CVL, correlating these changes with the parasite load and clinical signs. Splenic fragments were collected from 41 naturally infected animals for parasite load quantification by quantitative PCR, histopathological analysis and immunohistochemistry for CD3⁺, CD4⁺, and CD8⁺ T cells; CD21⁺ B cells; Ki-67⁺, IFN-γ⁺, and IL-10⁺ cells; and the MMP-9 and ADAM-10 enzymes. Laminin, collagen and fibronectin deposition were also evaluated. The animals were grouped according to the level of SWP organization. SWP disorganization was accompanied by a reduction in the quantity of lymphoid follicles/mm² (p > 0.0001). Animals with moderate to intense SWP disorganization showed more clinical signs (p = 0.021), higher laminin (p = 0.045) and collagen deposition (p = 0.036), higher MMP-9 expression (p = 0.035) and lower numbers of CD4⁺ T cells (p = 0.027) in the spleen than the animals with organized SWP. These data suggest that splenic structure and function are drastically altered and compromised during CVL.

Infected dogs play important roles in the transmission of visceral leishmaniasis. These dogs are considered reservoirs of parasites in urban areas and fail to mount an efficient anti-Leishmania immune response. However, the specific immunosuppression profile is not completely understood. In our report, we evaluate and discuss the morphophysiological alterations in the spleens of dogs with visceral leishmaniasis. We found an association between extracellular matrix alterations and a failure to control the parasite load. We suggest a role for these alterations in hindering an immune response that is otherwise able to control the parasite load, thereby leading to disease progression. Our research contributes to the current knowledge of the immunopathology of canine visceral leishmaniasis.

Internal Affairs: Tenascin-C as a Clinically Relevant, Endogenous Driver of Innate Immunity

To protect against danger, the innate immune system must promptly and accurately sense alarm signals, and mount an appropriate response to restore homeostasis. One endogenous trigger of immunity is tenascin-C, a large hexameric protein of the extracellular matrix. Upregulated upon tissue injury and cellular stress, tenascin-C is expressed during inflammation and tissue remodeling, where it influences cellular behavior by interacting with a multitude of molecular targets, including other matrix components, cell surface proteins, and growth factors. Here, we discuss how these interactions confer upon tenascin-C distinct immunomodulatory capabilities that make this matrix molecule necessary for efficient tissue repair. We also highlight in vivo studies that provide insight into the consequences of misregulated tenascin-C expression on inflammation and fibrosis during a wide range of inflammatory diseases. Finally, we examine how its unique expression pattern and inflammatory actions make tenascin-C a viable target for clinical exploitation in both diagnostic and therapeutic arenas.