α2β1 integrin regulates Th17 cell activity and its neutralization decreases the severity of collagen-induced arthritis

Genkwanin alleviates intervertebral disc degeneration via regulating ITGA2/PI3K/AKT pathway and inhibiting apoptosis and senescence

Intervertebral disc degeneration (IVDD) is a progressive degenerative disease influenced by various factors. Genkwanin, a known anti-inflammatory flavonoid, has not been explored for its potential in IVDD management. This study aims to investigate the effects and mechanisms of genkwanin on IVDD. In vitro, cell experiments revealed that genkwanin dose-dependently inhibited Interleukin-1β-induced expression levels of inflammatory factors (Interleukin-6, inducible nitric oxide synthase, cyclooxygenase-2) and degradation metabolic protein (matrix metalloproteinase-13). Concurrently, genkwanin upregulated the expression of synthetic metabolism genes (type II collagen, aggrecan). Moreover, genkwanin effectively reduced the phosphorylation of phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin, mitogen-activated protein kinase (MAPK), and nuclear factor-κB (NF-κB) pathways. Transcriptome sequencing analysis identified integrin α2 (ITGA2) as a potential target of genkwanin, and silencing ITGA2 reversed the activation of PI3K/AKT pathway induced by Interleukin-1β. Furthermore, genkwanin alleviated Interleukin-1β-induced senescence and apoptosis in nucleus pulposus cells. In vivo animal experiments demonstrated that genkwanin mitigated the progression of IVDD in the rat model through imaging and histological examinations. In conclusion, This study suggest that genkwanin inhibits inflammation in nucleus pulposus cells, promotes extracellular matrix remodeling, suppresses cellular senescence and apoptosis, through the ITGA2/PI3K/AKT, NF-κB and MAPK signaling pathways. These findings indicate that genkwanin may be a promising therapeutic candidate for IVDD.

The role of integrin family in bone metabolism and tumor bone metastasis

Integrins have been the research focus of cell-extracellular matrix adhesion (ECM) and cytokine receptor signal transduction. They are involved in the regulation of bone metabolism of bone precursor cells, mesenchymal stem cells (MSCs), osteoblasts (OBs), osteoclasts (OCs), and osteocytes. Recent studies expanded and updated the role of integrin in bone metabolism, and a large number of novel cytokines were found to activate bone metabolism pathways through interaction with integrin receptors. Integrins act as transducers that mediate the regulation of bone-related cells by mechanical stress, fluid shear stress (FSS), microgravity, hypergravity, extracellular pressure, and a variety of physical factors. Integrins mediate bone metastasis of breast, prostate, and lung cancer by promoting cancer cell adhesion, migration, and survival. Integrin-mediated targeted therapy showed promising prospects in bone metabolic diseases. This review emphasizes the latest research results of integrins in bone metabolism and bone metastasis and provides a vision for treatment strategies.

β1 Integrin induces adhesion and migration of human Th17 cells via Pyk2-dependent activation of P2X4 receptor

Integrin-mediated T-cell adhesion and migration is a crucial step in immune response and autoimmune diseases. However, the underlying signalling mechanisms are not fully elucidated. In this study, we examined the implication of purinergic signalling, which has been associated with T-cell activation, in the adhesion and migration of human Th17 cells across fibronectin, a major matrix protein associated with inflammatory diseases. We showed that the adhesion of human Th17 cells to fibronectin induces, via β1 integrin, a sustained release of adenosine triphosphate (ATP) from the mitochondria through the pannexin-1 hemichannels. Inhibition of ATP release or its degradation with apyrase impaired the capacity of the cells to attach and migrate across fibronectin. Inhibition studies identified a major role for the purinergic receptor P2X4 in T-cell adhesion and migration but not for P2X7 or P2Y₁₁ receptors. Blockade of P2X4 but not P2X7 or P2Y₁₁ receptors reduced cell adhesion and migration by inhibiting activation of β1 integrins, which is essential for ligand binding. Furthermore, we found that β1 integrin-induced ATP release, P2X4 receptor transactivation, cell adhesion and migration were dependent on the focal adhesion kinase Pyk2 but not FAK. Finally, P2X4 receptor inhibition also blocked fibronectin-induced Pyk2 activation suggesting the existence of a positive feedback loop of activation between β1 integrin/Pyk2 and P2X4 purinergic signalling pathways. Our findings uncovered an unrecognized link between β1 integrin and P2X4 receptor signalling pathways for promoting T-cell adhesion and migration across the extracellular matrix.

The regulatory roles of T helper cells in distinct extracellular matrix characterization in breast cancer

Background

Tumors are characterized by extracellular matrix (ECM) remodeling and stiffening. The ECM has been recognized as an important determinant of breast cancer progression and prognosis. Recent studies have revealed a strong link between ECM remodeling and immune cell infiltration in a variety of tumor types. However, the landscape and specific regulatory mechanisms between ECM and immune microenvironment in breast cancer have not been fully understood.

Methods

Using genomic data and clinical information of breast cancer patients obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, we conducted an extensive multi-omics analysis to explore the heterogeneity and prognostic significance of the ECM microenvironment. Masson and Sirius red staining were applied to quantify the contents of collagen in the ECM microenvironment. Tissue immunofluorescence (IF) staining was applied to identify T helper (Th) cells.

Results

We classified breast cancer patients into two ECM-clusters and three gene-clusters by consensus clustering. Significant heterogeneity in prognosis and immune cell infiltration have been found in these distinct clusters. Specifically, in the ECM-cluster with better prognosis, the expression levels of Th2 and regulatory T (Treg) cells were reduced, while the Th1, Th17 and T follicular helper (Tfh) cells-associated activities were significantly enhanced. The correlations between ECM characteristics and Th cells infiltration were then validated by clinical tissue samples from our hospital. The ECM-associated prognostic model was then constructed by 10 core prognostic genes and stratified breast cancer patients into two risk groups. Kaplan-Meier analysis showed that the overall survival (OS) of breast cancer patients in the high-risk group was significantly worse than that of the low-risk group. The risk scores for breast cancer patients obtained from our prognostic model were further confirmed to be associated with immune cell infiltration, tumor mutation burden (TMB) and stem cell indexes. Finally, the half-maximal inhibitory concentration (IC50) values of antitumor agents for patients in different risk groups were calculated to provide references for therapy targeting distinct ECM characteristics.

Conclusion

Our findings identify a novel strategy for breast cancer subtyping based on the ECM characterization and reveal the regulatory roles of Th cells in ECM remodeling. Targeting ECM remodeling and Th cells hold potential to be a therapeutic alternative for breast cancer in the future.

Anti-human platelet antigen-5b antibodies and fetal and neonatal alloimmune thrombocytopenia; incidental association or cause and effect?

Most cases of fetal and neonatal thrombocytopenia (FNAIT) are caused by maternal anti-human platelet antigen-1a antibodies (anti-HPA-1a). Anti-HPA-5b antibodies are the second most common antibodies in suspected FNAIT cases. Given the high prevalence of anti-HPA-5b antibodies in pregnant women delivering healthy newborns, the association with FNAIT may be coincidental. This review of the literature related to FNAIT using the MEDLINE database was conducted according to PRISMA guidelines. A retrospective analysis of a single-centre cohort of 817 suspected FNAIT cases was conducted. The pooled prevalence of anti-HPA-5b antibodies in unselected pregnant women of European descent was 1.96% (n = 3113), compared with 3.4% (n = 5003) in women with suspected FNAIT. We found weak evidence that a small proportion of pregnant women presenting with anti-HPA-5b antibodies will give birth to a newborn with mild thrombocytopenia. The neonatal platelet counts were not different between suspected FNAIT cases (n = 817) with and without maternal anti-HPA-5b antibodies. The prevalence of maternal anti-HPA-5b antibodies was not different between neonates with intracranial haemorrhage and healthy controls. The current experimental and epidemiological evidence does not support the hypothesis that anti-HPA-5b antibodies cause severe thrombocytopenia or bleeding complications in the fetus or newborn.

The Purinergic Receptor P2X4 Promotes Th17 Activation and the Development of Arthritis

Purinergic signaling plays a major role in T cell activation leading to IL-2 production and proliferation. However, it is unclear whether purinergic signaling contributes to the differentiation and activation of effector T cells. In this study, we found that the purinergic receptor P2X4 was associated with human Th17 cells but not with Th1 cells. Inhibition of P2X4 receptor with the specific antagonist 5-BDBD and small interfering RNA inhibited the development of Th17 cells and the production of IL-17 by effector Th17 cells stimulated via the CD3/CD28 pathway. Our results showed that P2X4 was required for the expression of retinoic acid-related orphan receptor C, which is the master regulator of Th17 cells. In contrast, inhibition of P2X4 receptor had no effect on Th1 cells and on the production of IFN-γ and it did not affect the expression of the transcription factor T-bet (T-box transcription factor). Furthermore, inhibition of P2X4 receptor reduced the production of IL-17 but not of IFN-γ by effector/memory CD4⁺ T cells isolated from patients with rheumatoid arthritis. In contrast to P2X4, inhibition of P2X7 and P2Y₁₁ receptors had no effects on Th17 and Th1 cell activation. Finally, treatment with the P2X4 receptor antagonist 5-BDBD reduced the severity of collagen-induced arthritis in mice by inhibiting Th17 cell expansion and activation. Our findings provide novel insights into the role of purinergic signaling in T cell activation and identify a critical role for the purinergic receptor P2X4 in Th17 activation and in autoimmune arthritis.

Immune Modulatory Properties of Collagen in Cancer

During tumor growth the extracellular matrix (ECM) undergoes dramatic remodeling. The normal ECM is degraded and substituted with a tumor-specific ECM, which is often of higher collagen density and increased stiffness. The structure and collagen density of the tumor-specific ECM has been associated with poor prognosis in several types of cancer. However, the reason for this association is still largely unknown. Collagen can promote cancer cell growth and migration, but recent studies have shown that collagens can also affect the function and phenotype of various types of tumor-infiltrating immune cells such as tumor-associated macrophages (TAMs) and T cells. This suggests that tumor-associated collagen could have important immune modulatory functions within the tumor microenvironment, affecting cancer progression as well as the efficacy of cancer immunotherapy. The effects of tumor-associated collagen on immune cells could help explain why a high collagen density in tumors is often correlated with a poor prognosis. Knowledge about immune modulatory functions of collagen could potentially identify targets for improving current cancer therapies or for development of new treatments. In this review, the current knowledge about the ability of collagen to influence T cell activity will be summarized. This includes direct interactions with T cells as well as induction of immune suppressive activity in other immune cells such as macrophages. Additionally, the potential effects of collagen on the efficacy of cancer immunotherapy will be discussed.

Salicylic acid-based nanomedicine with self-immunomodulatory activity facilitates microRNA therapy for metabolic skeletal disorders

Metabolic skeletal disorders remain a major clinical challenge. The complexity of this disease requires a strategy to address the net effects of both inflammation and impaired bone formation. microRNA-based gene therapy provides several therapeutic advantages to tackle these issues. Herein, we describe a microRNA-21 (miR-21) delivery system with an additional therapeutic effect from that of the delivery carrier itself. Poly (salicylic acid) (PSA) is, for the first time, synthesized via polycondensation of salicylic acid (SA), a bioactive ingredient widely used for anti-inflammation in medicine. PSA can self-assemble into nanoparticles (PSA-NPs) and can effectively deliver genes both in vitro and in vivo. The carrier was then attached to repetitive sequences of aspartate, serine, serine (DSS)₆ for delivering miRNAs specifically to bone-formation surfaces. In vitro studies showed that miR-21@PSA-NP could effectively realize the intracellular delivery of miR-21 with low toxicity, while in vivo results indicated that the miR-21@PSA-NP-DSS₆ prolonged blood circulation time, enhanced bone accumulation, and significantly improved the efficacy of miR-21-based bone anabolic therapy in osteoporotic mice. The constructed delivery system (miR-21@PSA-NP-DSS₆) inherited the advantages of both SA and miR-21, which could ameliorate bone-inflamed niche and rescued the impaired bone formation ability. The synergy of anti-inflammatory and pro-osteogenic effects significantly improved trabecular bone microstructure in osteoporotic mice. STATEMENT OF SIGNIFICANCE: The complexity of metabolic skeletal disorders requires a strategy to address the net effects of both inflammation and impaired bone formation. microRNA-based gene therapy provides several therapeutic advantages to tackle these issues. We develop a novel microRNA-21 delivery system with additional therapeutic effect from that of the gene carrier itself. Poly (salicylic acid) (PSA) nanoparticles, for the first time, synthesized via polycondensation of salicylic acid and can effectively deliver genes both in vitro and in vivo. The constructed delivery system (miR-21@PSA-NP-DSS₆) inherited the advantages of both SA (commonly used anti-inflammation drug in medicine) and miR-21 (a pro-osteogenic molecule), which could ameliorate bone-inflamed niche, rescued impaired bone formation ability and significantly improved trabecular bone microstructure in osteoporotic mice.

Inhibition of NF-κB signaling and HSP70/HSP90 proteins by newly synthesized hydrazide derivatives in arthritis model

In the current study, the N-benzylidene-4-((2-hydroxynaphthalene-1-yl) diazenyl) hydrazides (NCHDH and NTHDH) were evaluated against the Carrageenan- and CFA-induced models. During the preliminary investigation, the NCHDH and NTHDH treatment showed marked anti-inflammatory and analgesic activity against the Carrageenan-induced acute model. Once the anti-inflammatory activity was established against acute Carrageenan model, the NCHDH and NTHDH were evaluated against the chronic CFA-induced arthritis model. The NCHDH and NTHDH treatment markedly attenuated the inflammatory and analgesic parameters compared to CFA-treated group. Furthermore, the increase in the oxidative stress and attenuation of antioxidant enzymes has been reported following CFA administration. However, NCHDH and NTHDH treatment significantly induced the antioxidants and attenuated the oxidative stress markers. The CFA administration showed marked tailing of DNA; however, the NCHDH- and NTHDH-treated group preserved DNA integrity. Furthermore, the histological studies showed marked alteration in the CFA-treated group; however, the NCHDH and NTHDH treatment markedly improved the histological features. The Western blot, immunohistology, and ELISA assay revealed marked increase in the Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), Jun N-terminal Kinase (JNK), TNF-α, and COX-2 levels; however, the NCHDH and NTHDH attenuated their expressions significantly. Similarly, the NCHDH and NTHDH significantly induced the mRNA expression levels of heat shock proteins. The computational analysis showed significant binding interaction with various protein targets via multiple hydrogens, and hydrophobic bonds. The in vivo pharmacokinetic study was also performed to assess the various pharmacokinetic parameters. In conclusion, the NCHDH and NTHDH treatment showed significant anti-arthritic activity against Carrageenan and CFA models.

Activated neutrophils polarize protumorigenic interleukin-17A-producing T helper subsets through TNF-α-B7-H2-dependent pathway in human gastric cancer

RATIONALE

Neutrophils constitute massive cellular constituents in inflammatory human gastric cancer (GC) tissues, but their roles in pathogenesis of inflammatory T helper (Th) subsets are still unknown.

METHODS

Flow cytometry analysis and immunohistochemistry were used to analyze the responses and phenotypes of neutrophils in different samples from 51 patients with GC. Kaplan-Meier plots and Multivariate analysis for the survival of patients were used by log-rank tests and Cox proportional hazards models. Neutrophils and CD4+ T cells were purified and cultured for ex vivo, in vitro and in vivo regulation and function assays.

RESULTS

GC patients exhibited increased tumoral neutrophil infiltration with GC progression and poor patient prognosis. Intratumoral neutrophils accumulated in GC tumors via CXCL6/CXCL8-CXCR1-mediated chemotaxis, and expressed activated molecule CD54 and co-signaling molecule B7-H2. Neutrophils induced by tumors strongly expressed CD54 and B7-H2 in both dose- and time-dependent manners, and a close correlation was obtained between the expressions of CD54 and B7-H2 on intratumoral neutrophils. Tumor-derived tumor necrosis factor-α (TNF-α) promoted neutrophil activation and neutrophil B7-H2 expression through ERK-NF-κB pathway, and a significant correlation was found between the levels of TNF-α and CD54+ or B7-H2+ neutrophils in tumor tissues. Tumor-infiltrating and tumor-conditioned neutrophils effectively induced IL-17A-producing Th subset polarization through a B7-H2-dependent manner ex vivo and these polarized IL-17A-producing Th cells exerted protumorigenic roles by promoting GC tumor cell proliferation via inflammatory molecule IL-17A in vitro, which promoted the progression of human GC in vivo; these effects could be reversed when IL-17A is blocked. Moreover, increased B7-H2+ neutrophils and IL-17A in tumors were closely related to advanced GC progression and predicted poor patient survival.

CONCLUSION

We illuminate novel underlying mechanisms that TNF-α-activated neutrophils link B7-H2 to protumorigenic IL-17A-producing Th subset polarization in human GC. Blocking this pathological TNF-α-B7-H2-IL-17A pathway may be useful therapeutic strategies for treating GC.

ITGBL1 modulates integrin activity to promote cartilage formation and protect against arthritis

Developing and mature chondrocytes constantly interact with and remodel the surrounding extracellular matrix (ECM). Recent research indicates that integrin-ECM interaction is differentially regulated during cartilage formation (chondrogenesis). Integrin signaling is also a key source of the catabolic reactions responsible for joint destruction in both rheumatoid arthritis and osteoarthritis. However, we do not understand how chondrocytes dynamically regulate integrin signaling in such an ECM-rich environment. Here, we found that developing chondrocytes express integrin-β-like 1 (Itgbl1) at specific stages, inhibiting integrin signaling and promoting chondrogenesis. Unlike cytosolic integrin inhibitors, ITGBL1 is secreted and physically interacts with integrins to down-regulate activity. We observed that Itgbl1 expression was strongly reduced in the damaged articular cartilage of patients with osteoarthritis (OA). Ectopic expression of Itgbl1 protected joint cartilage against OA development in the destabilization of the medial meniscus-induced OA mouse model. Our results reveal ITGBL1 signaling as an underlying mechanism of protection against destructive cartilage disorders and suggest the potential therapeutic utility of targeting ITGBL1 to modulate integrin signaling in human disease.

Alpha2beta1 Integrin (VLA-2) Protects Activated Human Effector T Cells From Methotrexate-Induced Apoptosis

β1 integrins are critical for T cell migration, survival and costimulation. The integrin α2β1, which is a receptor for collagen, also named VLA-2, is a major costimulatory pathway of effector T cells and has been implicated in arthritis pathogenesis. Herein, we have examined its ability to promote methotrexate (MTX) resistance by enhancing effector T cells survival. Our results show that attachment of anti-CD3-activated human polarized Th17 cells to collagen but not to fibronectin or laminin led to a significant reduction of MTX-induced apoptosis. The anti-CD3+collagen-rescued cells still produce significant amounts of IL-17 and IFNγ upon their reactivation indicating that their inflammatory nature is preserved. Mechanistically, we found that the prosurvival role of anti-CD3+collagen involves activation of the MTX transporter ABCC1 (ATP Binding Cassette subfamily C Member 1). Finally, the protective effect of collagen/α2β1 integrin on MTX-induced apoptosis also occurs in memory CD4⁺ T cells isolated from rheumatoid arthritis (RA) patients suggesting its clinical relevance. Together these results show that α2β1 integrin promotes MTX resistance of effector T cells, and suggest that it could contribute to the development of MTX resistance that is seen in RA.

Gene and Protein Expression Profiles in a Mouse Model of Collagen-Induced Arthritis

The risk of rheumatoid arthritis (RA), an autoimmune disease, in the elderly population increases along with that of atherosclerosis, cardiovascular disease, type 2 diabetes, and Alzheimer's disease. Identifying specific biomarkers for RA can clarify the underlying molecular mechanisms and can aid diagnosis and patient care. To this end, the present study investigated the genes and proteins that are differentially expressed in RA using a mouse collagen-induced arthritis (CIA) model. We performed gene microarray and proteome array analyses using blood samples from the mice and found that 50 genes and 24 proteins were upregulated and 48 genes were downregulated by more than 2-fold in the CIA model relative to the control. The gene microarray and proteome array results were validated by evaluating the expression levels of select genes and proteins by real-time PCR and western blotting, respectively. We found that the level of integrin α2, which has not been previously reported as a biomarker of RA, was significantly increased in CIA mice as compared to controls. These findings provide a set of novel biomarkers that can be useful for diagnosing and evaluating the progression of RA.

Inflammatory Th17 Cells Express Integrin αvβ3 for Pathogenic Function

Interleukin-23 (IL-23) is required for inflammatory Th17 cell function in experimental autoimmune encephalomyelitis (EAE), and IL-23 blockade reduces the number of effector Th17 cells in the CNS. We report that pro-inflammatory Th17 cells express high integrin β3 that is IL-23 dependent. Integrin β3 was not upregulated on all activated T cells; rather, integrin β3 was upregulated along with its functional partner integrin αv on effector Th17 cells and "ex-Th17" cells, and αvβ3(hi) RORγt(+) cells expanded during EAE. Integrin αvβ3 inhibitors ameliorated clinical signs of EAE, and integrin β3 deficiency on CD4(+) T cells alone was sufficient to block EAE induction. Furthermore, integrin-β3-deficient Th17 cells, but not Th1 cells, were impaired in their ability to induce EAE. Integrin β3(-/-) T cells induced smaller demyelinated lesions and showed reduced spread and accumulation within the CNS, corresponding with impaired extracellular-matrix-mediated migration. Hence, integrin β3 is required for Th17 cell-mediated autoimmune CNS inflammation.

The role of "bone immunological niche" for a new pathogenetic paradigm of osteoporosis

Osteoporosis is characterized by low bone mass and microarchitectural deterioration of bone tissue. The etiology and pathogenetic mechanisms of osteoporosis have not been clearly elucidated. Osteoporosis is linked to bone resorption by the activation of the osteoclastogenic process. The breakdown of homeostasis among pro- and antiosteoclastogenic cells causes unbalanced bone remodeling. The complex interactions among these cells in the bone microenvironment involve several mediators and proinflammatory pathways. Thus, we may consider the bone microenvironment as a complex system in which local and systemic immunity are regulated and we propose to consider it as an "immunological niche." The study of the "bone immunological niche" will permit a better understanding of the complex cell trafficking which regulates bone resorption and disease. The goal of a perfect therapy for osteoporosis would be to potentiate good cells and block the bad ones. In this scenario, additional factors may take part in helping or hindering the proosteoblastogenic factors. Several proosteoblastogenic and antiosteoclastogenic agents have already been identified and some have been developed and commercialized as biological therapies for osteoporosis. Targeting the cellular network of the "bone immunological niche" may represent a successful strategy to better understand and treat osteoporosis and its complications.

Alpha2beta1 integrin in cancer development and chemoresistance

Extracellular matrix, via its receptors the integrins, has emerged as a crucial factor in cancer development. The α2β1 integrin is a major collagen receptor that is widely expressed and known to promote cell migration and control tissue homeostasis. Growing evidence suggests that it can be a key pathway in cancer. Recent studies have shown that α2β1 integrin is a regulator of cancer metastasis either by promoting or inhibiting the dissemination process of cancer cells. The α2β1 integrin signaling can also enhance tumor angiogenesis. Emerging evidence supports a role for α2β1 integrin in cancer chemoresistance especially in hematological malignancies originating from the T cell lineage. In addition, α2β1 integrin has been associated with cancer stem cells. In this review, we will discuss the complex role of α2β1 integrin in these processes. Collagen is a major matrix protein of the tumor microenvironment and thus, understanding how α2β1 integrin regulates cancer pathogenesis is likely to lead to new therapeutic approaches and agents for cancer treatment.

Sulfonamide inhibitors of α2β1 integrin reveal the essential role of collagen receptors in in vivo models of inflammation

Small molecule inhibitors of α2β1 integrin, a major cellular collagen receptor, have been reported to inhibit platelet function, kidney injury, and angiogenesis. Since α2β1 integrin is abundantly expressed on various inflammation-associated cells, we tested whether recently developed α2β1 blocking sulfonamides have anti-inflammatory properties. Integrin α2β1 inhibitors were shown to reduce the signs of inflammation in arachidonic acid-induced ear edema, PAF stimulated air pouch, ovalbumin-induced skin hypersensitivity, adjuvant arthritis, and collagen-induced arthritis. Thus, these sulfonamides are potential drugs for acute and allergic inflammation, hypersensitivity, and arthritis. One sulfonamide with potent anti-inflammatory activity has previously been reported to be selective for activated integrins, but not to inhibit platelet function. Thus, the experiments also revealed fundamental differences in the action of nonactivated and activated α2β1 integrins in inflammation when compared to thrombosis.