Rearrangement Of Extracellular Matrix Research Articles

Targeting cardiac fibrosis with Chimeric Antigen Receptor-Engineered Cells.

Cardiac fibrosis poses a significant challenge in cardiovascular diseases due to its intricate pathogenesis, and there is currently no standardized and effective treatment approach. The fibrotic process entails the involvement of various cell types and molecular mechanisms, such as fibroblast activation and proliferation, increased collagen synthesis, and extracellular matrix rearrangement. Traditional therapies often fall short in efficacy or carry substantial side effects. However, recent studies have shown that Chimeric Antigen Receptor T (CAR-T) cells can selectively target and eliminate activated cardiac fibroblasts (CFs) in mice, leading to reduced cardiac fibrosis and improved myocardial tissue compliance. This breakthrough presents a new and promising avenue for treating cardiac fibrosis. Currently, CAR-T cell-based therapy for cardiac fibrosis is undergoing animal experimentation, indicating ample scope for enhancement. Future investigations could explore the application of CAR cell therapy in cardiac fibrosis treatment, including the potential of CAR-natural killer (CAR-NK) cells and CAR macrophages (CAR-M), offering novel insights and strategies for combating cardiac fibrosis.

Contents of matrix metalloproteinase type 2 (MMP-2) and complexes MMP-9/TIMP-1, MMP-2/TIMP-2, and total cholesterol in practically healthy people and patients with hypertension

Arterial hypertension (AH) is the most common age-associated disease among the working population. Polyetiology of AH requires a more thorough definition and study of its predictors aiming for understanding the role of external influences, as well as detection of genetic polymorphisms at early stages, in order to limit their implementation. The scientific reviews discuss the important role of abnormal vascular remodeling in the pathogenesis of hypertension. The main factor of such alterations is the rearrangement of extracellular matrix due to matrix metalloproteinases (MMP), the zinc-dependent enzymes with a wide substrate specificity. In addition, in more than 70% of cases, AH is combined with lipid metabolism disorders, including an increase in cholesterol levels. These mechanisms should be taken into account when assessing risk factors for development of cardiovascular accidents. The role of MMP-2 and the complexes MMP- 9/ TIMP- 1, MMP-2/TIMP-2 in pathogenesis of vascular restructuring is insufficiently described in the review articles. The article presents our results of studying the system of proteolytic enzymes and the level of total cholesterol in 110 practically healthy people and 90 persons with AH aged 18 to 74 years old. The levels of MMP-2, MMP-9/ TIMP- 1, MMP-2/TIMP-2 complexes in blood serum were studied by the sandwich variant of ELISA technique. Statistical processing of the obtained data was carried out using the analytical software IBM SPSS Statistics, v. 22.0.1. It was found that in the groups of women, regardless of the presence, or absence of pathology, the level of total cholesterol is higher if compared with male subjects. MMP-2 values were low both in the general group of practically healthy people, regardless of gender, and in the group of men with hypertension. Proteolytic activity of MMP-2 shows a broader substrate activity in women with hypertension. In the group of practically healthy men and women, we have registered lower levels of the studied MMP complexes and their tissue inhibitors. An imbalance in the proteolysis/antiproteolysis system is observed both in the group of hypertensive women with more pronounced effects upon migration, proliferation and apoptosis of smooth muscle cells, endothelial and inflammatory cells, thus determining formation of intima and arterial remodeling, as well as in the group of men with hypertension with predominance of remodeling factors that affects the rigidity of vascular wall.

Link between insulin resistance and skeletal muscle extracellular matrix remodeling.

Skeletal muscle is the main metabolic tissue responsible for glucose homeostasis in the body. It is surrounded by the extracellular matrix (ECM) consisting of three layers: epimysium, perimysium, and endomysium. ECM plays an important role in the muscle, as it provides integrity and scaffolding cells. The observed disturbances in this structure are related to the abnormal remodeling of the ECM (through an increase in the concentration of its components). ECM rearrangement may impair insulin action by increasing the physical barrier to insulin transport and reducing insulin transport into muscle cells as well as by directly inhibiting insulin action through integrin signaling. Thus, improper ECM remodeling may contribute to the development of insulin resistance (IR) and related comorbidities. In turn, IR-associated conditions may further aggravate disturbances of ECM in skeletal muscle. This review describes the major components of the ECM that are necessary for its proper function. Particular attention was also paid to receptors (integrins) involved in the signaling of metabolic pathways. Finally, changes in ECM components in the context of clinical and animal studies are discussed. This article will help the reader to systematize knowledge related to the ECM and to better understand the relationship between ECM remodeling and IR, and its role in the pathogenesis of T2DM. The information in this article presents the concept of the role of ECM and its remodeling in the pathogenesis of IR, which may contribute to developing new therapeutic solutions.

Regulatory roles of fibronectin and integrin α5 in reorganization of the actin cytoskeleton and completion of adipogenesis.

Cellular differentiation is characterized by changes in cell morphology that are largely determined by actin dynamics. We previously showed that depolymerization of the actin cytoskeleton triggers the differentiation of preadipocytes into mature adipocytes as a result of inhibition of the transcriptional coactivator activity of megakaryoblastic leukemia 1 (MKL1). The extracellular matrix (ECM) influences cell morphology via interaction with integrins, and reorganization of the ECM is associated with cell differentiation. Here we show that interaction between actin dynamics and ECM rearrangement plays a key role in adipocyte differentiation. We found that depolymerization of the actin cytoskeleton precedes disruption and degradation of fibrillar fibronectin (FN) structures at the cell surface after the induction of adipogenesis in cultured preadipocytes. A FN matrix suppressed both reorganization of the actin cytoskeleton into the pattern characteristic of adipocytes and terminal adipocyte differentiation, and these inhibitory effects were overcome by knockdown of integrin α5 (ITGα5). Peroxisome proliferator-activated receptor γ was required for down-regulation of FN during adipocyte differentiation, and MKL1 was necessary for the expression of ITGα5. Our findings suggest that cell-autonomous down-regulation of FN-ITGα5 interaction contributes to reorganization of the actin cytoskeleton and completion of adipocyte differentiation.

Tissue transglutaminase activates integrin-linked kinase and β-catenin in ovarian cancer

Ovarian cancer (OC) is the most lethal gynecological cancer. OC cells have high proliferative capacity, are invasive, resist apoptosis, and tumors often display rearrangement of extracellular matrix (ECM) components, contributing to accelerated tumor progression. The multifunctional protein tissue transglutaminase (TG2) is known to be secreted in the tumor microenvironment, where it interacts with fibronectin (FN) and the cell surface receptor integrin β1. However, the mechanistic role of TG2 in cancer cell proliferation is unknown. Here, we demonstrate that TG2 directly interacts with and facilitates the phosphorylation and activation of the integrin effector protein integrin-linked kinase (ILK) at Ser246. We show that TG2 and p-Ser246-ILK form a complex that is detectable in patient-derived OC primary cells grown on FN-coated slides. In addition, we show that coexpression of TGM2 and ILK correlates with poor clinical outcome. Mechanistically, we demonstrate that TG2-mediated ILK activation causes phosphorylation of glycogen synthase kinase-3α/β, allowing β-catenin nuclear translocation and transcriptional activity. Furthermore, inhibition of TG2 and ILK using small molecules, neutralizing antibodies, or shRNA-mediated knockdown blocks cell adhesion to the FN matrix, as well as the Wnt receptor response to the Wnt-3A ligand, and ultimately, cell adhesion, growth, and migration. In conclusion, we demonstrate that TG2 directly interacts with and activates ILK in OC cells and tumors and define a new mechanism that links ECM cues with β-catenin signaling in OC. These results suggest a central role of TG2–FN–integrin clusters in ECM rearrangement and indicate that downstream effector ILK may represent a potential new therapeutic target in OC.

Abstract 995: Tissue transglutaminase regulates integrin-linked kinase and beta-catenin signaling in ovarian cancer cells

Abstract Ovarian cancer (OC) is the most lethal gynecological cancer characterized by an enhanced migratory capacity, invasiveness, elevated resistance to apoptosis, and rearrangement of extra-cellular matrix (ECM) components. In OC, the interaction between fibronectin (FN) and the β1 integrins activates the adaptor protein integrin linked kinase (ILK) that acts as central hub integrating the mechanical forces with the activation of various signaling pathways, leading to cell survival, proliferation, and migration. ILK overexpression was correlated with OC progression and its functional inhibition blocked tumorigenicity by inactivation of glycogen synthase kinase-3α/β (GSK-3α/β) and the β-catenin-TCF/LEF1 transcriptional activity, thus pointing towards the direct involvement of ILK as a modulator of the crosstalk between ECM and the canonical Wnt signaling. However, the connection between integrins and β-catenin remains poorly understood. The multifunctional protein tissue transglutaminase (TG2) with enzymatic and scaffold functions is an important molecule secreted in the tumor microenvironment where it modulates oncogenic signaling by interacting with FN and integrins. Previously, we demonstrated that TG2/FN/β1 integrin clusters regulated β-catenin activation, correlating with OC progression. Here, we investigated whether TG2-FN interaction is essential to activate the integrin-ILK axis, thereby stabilizing β-catenin. First, we demonstrate that TG2-expressing OC cells plated on FN matrix increase the pool of active p-ILKSer246. Confocal microscopy shows that TG2 co-localizes with p-ILKSer246 in OC cells and that the presence of FN matrices is instrumental in the formation of active TG2/p-ILKSer246 clusters. Further, proximity ligation assay analysis reveals that each protein of the ternary TG2/FN/β1 integrin complex actively engages with p-ILKSer246 in primary ovarian tumor cells, supporting the functional relevance of TG2-mediated outside in transduction signals in vivo. Second, we show that TG2-mediated ILK activation mechanistically amplifies the response of OC cells to Wnt-3A treatment, leading to the inhibitory phosphorylation of the GSK-3α/β at Ser21/9, which in turn allows β-catenin nuclear translocation and transcriptional activity. Finally, we evaluate whether the TG2-ILK complex has functional outcomes. In the presence of an active TG2/p-ILKSer246 axis, Wnt-3a treatment efficiently increases proliferation and migration in OC cells compared to control, whereas the inhibitory anti-TG2 blocking antibody (clone 4G3) directed against the FN-binding domain of TG2 and ILK inhibition by the small molecule cpd-22 drastically reduce the Wnt-3A impact on the OC cell proliferative and migratory capacity. In sum, here we demonstrate that TG2 directly activates ILK and define a new mechanism which links ECM cues with β-catenin signaling in OC. Citation Format: Salvatore Condello, Rula Atwani, Daniela Matei. Tissue transglutaminase regulates integrin-linked kinase and beta-catenin signaling in ovarian cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 995.

Reciprocal cell-ECM dynamics generate supracellular fluidity underlying spontaneous follicle patterning

During vertebrate embryogenesis, cell collectives engage in coordinated behavior to form tissue structures of increasing complexity. In the avian skin, assembly into follicles depends on intrinsic mechanical forces of the dermis, but how cell mechanics initiate pattern formation is not known. Here, we reconstitute the initiation of follicle patterning exvivo using only freshly dissociated avian dermal cells and collagen. We find that contractile cells physically rearrange the extracellular matrix (ECM) and that ECM rearrangement further aligns cells. This exchange transforms a mechanically unlinked collective of dermal cells into a continuum, with coherent, long-range order. Combining theory with experiment, we show that this ordered cell-ECM layer behaves as an active contractile fluid that spontaneously forms regular patterns. Our study illustrates a role for mesenchymal dynamics in generating cell-level ordering and tissue-level patterning through a fluid instability-processes that may be at play across morphological symmetry-breaking contexts.

The Dual Effect of Rho-Kinase Inhibition on Trabecular Meshwork Cells Cytoskeleton and Extracellular Matrix in an In Vitro Model of Glaucoma.

The trabecular meshwork (TM) is the main site of drainage of the aqueous humor, and its dysfunction leads to intraocular pressure elevation, which is one of the main risk factors of glaucoma. We aimed to compare the effects on cytoskeleton organization and extracellular matrix (ECM) of latanoprost (LT) and a Rho-kinase inhibitor (ROCKi) on a transforming growth factor beta2 (TGF-β2)-induced glaucoma-like model developed from primary culture of human TM cells (pHTMC). The TGF-β2 stimulated pHTMC were grown and incubated with LT or a ROCKi (Y-27632) for 24 h. The expression of alpha-smooth muscle actin (αSMA) and fibronectin (FN), and phosphorylation of the myosin light chain (MLC-P) and Cofilin (Cofilin-P) were evaluated using immunofluorescence and Western blot. The architectural modifications were studied in a MatrigelTM 3D culture. TGF-β2 increased the expression of αSMA and FN in pHTMC and modified the cytoskeleton with cross-linked actin network formation. LT did not alter the expression of αSMA but decreased FN deposition. The ROCKi decreased TGF-β2-induced αSMA and FN expression, as well as MLC-P and Cofilin-P, and stimulated the cells to recover a basal cytoskeletal arrangement. In the preliminary 3D study, pHTMC organized in a mesh conformation showed the widening of the TM under the effect of Y-27632. By simultaneously modifying the organization of the cytoskeleton and the ECM, with fibronectin deposition and overexpression, TGF-β2 reproduced the trabecular degeneration described in glaucoma. The ROCKi was able to reverse the TGF-β2-induced cytoskeletal and ECM rearrangements. LT loosened the extracellular matrix but had no action on the stress fibers.

Exosomes and the extracellular matrix: a dynamic interplay in cancer progression.

Exosomes are a subtype of extracellular vesicles (EVs) composed of a lipid bilayer, which carry various cargoes such as nucleic acids, proteins, and bioactive lipids. Cancer cells release exosomes to promote cell communication and interaction with the extracellular matrix (ECM). ECM regulates the secretion and uptake of exosomes. Moreover, the cargo of exosomes can control ECM remodeling, thus affecting cancer progression. Aside from the rearrangement of ECM, exosomal cargo also modulates different signaling pathways that maintain homeostasis and play a major role in tumor growth and immune evasion in the tumor microenvironment (TME). Exosomes are now widely recognized as circulating biomarkers for diagnosis and prognosis. Their role in cancer initiation, progression, and chemoresistance is becoming increasingly clear from preclinical and clinical investigations, thereby gaining interest for their potential use as cancer diagnostics tools, but also for the development of future innovative cancer therapeutics. In this mini review we outline and discuss the correlation between exosomes, TME and cancer progression, while focusing on the potential role of exosomes as diagnostic and prognostic biomarkers, as well as therapeutic vehicles for drug delivery.

Gene Expression Response to Stony Coral Tissue Loss Disease Transmission in M. cavernosa and O. faveolata From Florida

Since 2014, corals within Florida’s Coral Reef have been dying at an unprecedented rate due to stony coral tissue loss disease (SCTLD). Here we describe the transcriptomic outcomes of three different SCTLD transmission experiments performed at the Smithsonian Marine Station and Mote Marine Laboratory between 2019 and 2020 on the corals Orbicella faveolata and Montastraea cavernosa. Overall, diseased O. faveolata had 2194 differentially expressed genes (DEGs) compared with healthy colonies, whereas diseased M. cavernosa had 582 DEGs compared with healthy colonies. Many significant DEGs were implicated in immunity, extracellular matrix rearrangement, and apoptosis. These included, but not limited to, peroxidases, collagens, Bax-like, fibrinogen-like, protein tyrosine kinase, and transforming growth factor beta. A gene module was identified that was significantly correlated to disease transmission. This module possessed many apoptosis and immune genes with high module membership indicating that a complex apoptosis and immune response is occurring in corals during SCTLD transmission. Overall, we found that O. faveolata and M. cavernosa exhibit an immune, apoptosis, and tissue rearrangement response to SCTLD. We propose that future studies should focus on examining early time points of infection, before the presence of lesions, to understand the activating mechanisms involved in SCTLD.

Identification of Molecular Mechanisms Related to Pig Fatness at the Transcriptome and miRNAome Levels.

Fat deposition and growth rate are closely related to pork quality and fattening efficiency. The next-generation sequencing (NGS) approach for transcriptome and miRNAome massive parallel sequencing of adipocyte tissue was applied to search for a molecular network related to fat deposition in pigs. Pigs were represented by three breeds (Large White, Pietrain, and Hampshire) that varied in fat content within each breed. The obtained results allowed for the detection of significant enrichment of Gene Ontology (GO) terms and pathways associated directly and indirectly with fat deposition via regulation of fatty acid metabolism, fat cell differentiation, inflammatory response, and extracellular matrix (ECM) organization and disassembly. Moreover, the results showed that adipocyte tissue content strongly affected the expression of leptin and other genes related to a response to excessive feed intake. The findings indicated that modification of genes and miRNAs involved in ECM rearrangements can be essential during fat tissue growth and development in pigs. The identified molecular network within genes and miRNAs that were deregulated depending on the subcutaneous fat level are proposed as candidate factors determining adipogenesis, fatness, and selected fattening characteristics in pigs.

Dopamine Receptor Activation Modulates the Integrity of the Perisynaptic Extracellular Matrix at Excitatory Synapses.

In the brain, Hebbian-type and homeostatic forms of plasticity are affected by neuromodulators like dopamine (DA). Modifications of the perisynaptic extracellular matrix (ECM), which control the functions and mobility of synaptic receptors as well as the diffusion of transmitters and neuromodulators in the extracellular space, are crucial for the manifestation of plasticity. Mechanistic links between synaptic activation and ECM modifications are largely unknown. Here, we report that neuromodulation via D1-type DA receptors can induce targeted ECM proteolysis specifically at excitatory synapses of rat cortical neurons via proteases ADAMTS-4 and -5. We showed that receptor activation induces increased proteolysis of brevican (BC) and aggrecan, two major constituents of the adult ECM both in vivo and in vitro. ADAMTS immunoreactivity was detected near synapses, and shRNA-mediated knockdown reduced BC cleavage. We have outlined a molecular scenario of how synaptic activity and neuromodulation are linked to ECM rearrangements via increased cAMP levels, NMDA receptor activation, and intracellular calcium signaling.

Convection-Enhanced Delivery: Connection to and Impact of Interstitial Fluid Flow.

Convection-enhanced delivery (CED) is a method used to increase transport of therapeutics in and around brain tumors. CED works through locally applying a pressure differential to drive fluid flow throughout the tumor, such that convective forces dominate over diffusive transport. This allows therapies to bypass the blood brain barrier that would otherwise be too large or solely rely on passive diffusion. However, this also drives fluid flow out through the tumor bulk into surrounding brain parenchyma, which results in increased interstitial fluid (IF) flow, or fluid flow within extracellular spaces in the tissue. IF flow has been associated with altered transport of molecules, extracellular matrix rearrangement, and triggering of cellular motility through a number of mechanisms. Thus, the results of a simple method to increase drug delivery may have unintended consequences on tissue morphology. Clinically, prediction of dispersal of agents via CED is important to catheter design, placement, and implementation to optimize contact of tumor cells with therapeutic agent. Prediction software can aid in this problem, yet we wonder if there is a better way to predict therapeutic distribution based simply on IF flow pathways as determined from pre-intervention imaging. Overall, CED based therapy has seen limited success and we posit that integration and appreciation of altered IF flow may enhance outcomes. Thus, in this manuscript we both review the current state of the art in CED and IF flow mechanistic understanding and relate these two elements to each other in a clinical context.

SUN-336 Autocrine / Paracrine Growth Hormone (GH) Drives Multimodal Therapy Resistance in Growth Hormone Receptor (GHR)-expressing Human Cancers

Data from cell culture, mice, and human epidemiological studies have identified and validated growth hormone receptor (GHR) expression and growth hormone (GH) action as an oncogenic factor in cancer. Recent studies by us and others have revealed a unique aspect of GH mediated endocrine regulation of pharmacological therapy resistance in human melanoma and breast cancer. GH overexpression was found to not only promote tumor proliferation, migration, and invasion but also associated with refractoriness towards radiation and chemotherapy. However, the underlying mechanisms of the observed GH effects were unknown. To understand the molecular details of therapy resistance of the GH-GHR axis in cancer, we have used four different GHR-positive human cancers of pancreas, kidney, lung, and melanoma. We have identified multi-modal therapy resistance pathways regulated by GH action in these tumors, which was absent in GHR-negative cell lines. Here we report our latest findings explaining the method of action of GH driven cancer therapy resistance and the associated mediators. Expression of GHR and an autocrine / paracrine GH production, elicited specifically by onset of therapy (chemo, targeted, radiation) upregulates (i) ATP-binding cassette containing multidrug efflux pumps, (ii) phenotype switch via epithelial-to-mesenchymal transition, (iii) extracellular matrix rearrangement to promote tumor invasion, and (iv) cytokine mediated immunoediting. Attenuation of the GHR activity using GHR-antagonists or CRISPR-Cas9 mediated GHR knockout severely sensitized the cells towards therapy. In vivo studies using syngeneic mouse models and a thorough analyses of the TCGA data provide robust confirmation to our in vitro findings. Based on the above and ongoing studies in different mouse models of GH action, we speculate that targeting GHR as an adjuvant in cancer therapeutics might synergize therapeutic applications and lead towards a significantly improved prognosis for GHR-positive cancers.

Osmo-inelastic response of the intervertebral disc.

The intervertebral disc exhibits a complex inelastic response characterized by relaxation, hysteresis during cyclic loading and rate dependency. All these inelastic phenomena depend on osmotic interactions between disc tissues and their surrounding chemical environment. Coupling between osmotic and inelastic effects is not fully understood, so this article aimed to study the influence of chemical conditions on the inelastic behaviour of the intervertebral disc in response to different modes of loading. A total of 18 non-frozen 'motion segments' (two vertebrae and the intervening soft tissues) were dissected from the cervical spines of mature sheep. The motion segments were loaded in tension, compression and torsion at various loading rates and saline concentrations. Analysis of variance showed that saline concentration significantly influenced inelastic effects in tension and especially in compression (p < 0.05), but not in torsion. Opposite effects were seen in tension and compression. An interpretation of the underlying osmo-inelastic mechanisms is proposed in which two sources of inelastic effects are identified, that is, extracellular matrix rearrangements and fluid exchange created by osmosis.

Matrix Metalloproteinase 2: A Possible Role inTooth Development and Eruption

Introduction: Tooth development results from a highly coordinated epithelial-mesenchyme interaction in which mesenchyme cells originate the dental papilla and dental follicle, while ectodermal cells originate the enamel organ. Simultaneously, bone tissue is formed around the developing tooth, trapping it in a bony crypt. Tooth eruption requires the resorption of the coronal part of the bony crypt, followed by degradation of the lamina propria, most likely by metalloproteinases (MMPs) activity. Objectives: The aim of this research was to determine MMP-2 expression in the dental germ cells (ameloblasts, odontoblasts, dental papilla and dental follicle) and surrounding tissues (alveolar bone and lamina propria) of rat molars throughout the eruptive process. Material and Methods: A total of 24 rats (4,6,9,11,14 and 16 days old) were used in this study. MMP-2 was detected through immunohistochemistry. A qualitative analysis was performed to investigate the expression of MMP-2 in the dental germ cells, lamina propria, and coronal and basal regions of the bony crypt. Results: MMP-2 expression was observed in the dental papilla cells, dental follicle, ameloblasts, odontoblasts and bone cells from the coronal and basal regions of the bony crypt. MMP-2 was also detected in the lamina propria during the mucosal penetration stage of tooth eruption. Conclusion: We conclude that MMP-2 may be important for the extracellular matrix rearrangement necessary for tooth development and secretion of its mineralized tissues. We also conclude that MMP-2 may play a role in the extensive tissue remodeling during the intra-and-extra-osseous phases of the tooth eruption process.

New Insights into the Occurrence of Matrix Metalloproteases -2 and -9 in a Cohort of Breast Cancer Patients and Proteomic Correlations

Matrix metalloproteases (MMPs) are a family of well-known enzymes which operate prevalently in the extracellular domain, where they fulfil the function of remodeling the extracellular matrix (ECM). Within the 26 family members, encoded by 24 genes in humans, MMP-2 and MMP-9 have been regarded as primarily responsible for the basement membrane and peri-cellular ECM rearrangement. In cases of infiltrating carcinomas, which arise from the epithelial tissues of a gland or of an internal organ, a marked alteration of the expression and the activity levels of both MMPs is known to occur. The present investigation represents the continuation and upgrading of our previous studies, now focusing on the occurrence and intensity levels of MMP-2 and -9 and their proteomic correlations in a cohort of 80 breast cancer surgical tissues.

Cellular Reorganization Plays a Vital Role in Acupuncture Analgesia.

Background: Acupuncture has a long history of relieving many forms of pain. However, many of acupuncture's mechanisms are still unknown and/or misunderstood. Objective: This review looks at past research on many different methods and targets of study related to acupuncture. The main focus is upon the importance of connective-tissue planes in and around acupuncture points. Method: Relevant articles from journals as well as books on the topic were searched manually for information related to the topic. Results: Various studies offered different (and sometimes interrelated) mechanisms for how acupuncture needling results in analgesia among other effects. Emerging evidence, however, has shown the increasing importance of extracellular matrix rearrangements that result in lower mechanical stress states of surrounding tissues. This leads to lower constant stimulation of regional mechanoreceptors, in turn, reducing chronic pain and discomfort. Conclusions: The extracellular matrix has emerged as an important area of study on the effects of acupuncture needling.

Tissue transglutaminase in astrocytes is enhanced by inflammatory mediators and is involved in the formation of fibronectin fibril-like structures

BackgroundDuring multiple sclerosis (MS) lesion formation, inflammatory mediators are produced by microglial cells and invading leukocytes. Subsequently, hypertrophic astrocytes fill the lesion and produce extracellular matrix (ECM) proteins that together form the astroglial scar. This is beneficial because it seals off the site of central nervous system (CNS) damage. However, astroglial scarring also forms an obstacle that inhibits remyelination of brain lesions. This is possibly an important cause for incomplete remyelination of the CNS in early stage MS patients and for failure of remyelination when the disease progresses. Tissue transglutaminase (TG2), a Ca2+-dependent enzyme that can cross-link proteins, appears in astrocytes in inflammatory MS lesions and may contribute to the rearrangement of ECM protein deposition and aggregation.MethodsThe effect of different inflammatory mediators on TG2 and fibronectin, an ECM protein, protein levels was examined in primary rat microglia and astrocytes by western blotting. Also, TG2 activity was analyzed in primary rat astrocytes by a TG activity assay. To determine the role of TG2 in the deposition and cross-linking of fibronectin, a TG2 inhibitor and TG2 knockdown astrocytes were used.ResultsOur data show that under inflammatory conditions in vitro, TG2 production is enhanced in astrocytes and microglia. We observed that in particular, astrocytes produce fibronectin that can be cross-linked and aggregated by exogenous TG2. Moreover, inflammatory stimulus-induced endogenously produced TG2 is involved in the appearance of morphological fibril-like fibronectin deposits but does not lead to cross-linked fibronectin aggregates.ConclusionsOur in vitro observations suggest that during MS lesion formation, when inflammatory mediators are produced, astrocyte-derived TG2 may contribute to ECM rearrangement, and subsequent astroglial scarring.

Matrix Metalloproteinase-2 Activity is Associated with Divergent Regulation of Calponin-1 in Conductance and Resistance Arteries in Hypertension-induced Early Vascular Dysfunction and Remodelling.

Matrix metalloproteinase (MMP)-2 participates in hypertension-induced maladaptive vascular remodelling by degrading extra- and intracellular proteins. The consequent extracellular matrix rearrangement and phenotype switch of vascular smooth muscle cells (VSMCs) lead to increased cellular migration and proliferation. As calponin-1 degradation by MMP-2 may lead to VSMC proliferation during hypertension, the hypothesis of this study is that increased MMP-2 activity contributes to early hypertension-induced maladaptive remodelling in conductance and resistance arteries via regulation of calponin-1. The main objective was to analyse whether MMP-2 exerts similar effects on the structure and function of the resistance and conductance arteries during early hypertension. Two-kidney, one-clip (2K-1C) hypertensive male rats and corresponding controls were treated with doxycycline (30 mg/kg/day) or water until reaching one week of hypertension. Systolic blood pressure was increased in 2K-1C rats, and doxycycline did not reduce it. Aortas and mesenteric arteries were analysed. MMP-2 activity and expression were increased in both arteries, and doxycycline reduced it. Significant hypertrophic remodelling and VSMC proliferation were observed in aortas but not in mesenteric arteries of 2K-1C rats. The contractility of mesenteric arteries to phenylephrine was increased in 2K-1C rats, and doxycycline prevented this alteration. The potency of phenylephrine to contract aortas of 2K-1C rats was increased, and doxycycline decreased it. Whereas calponin-1 expression was increased in 2K-1C mesenteric arteries, calponin-1 was reduced in aortas. Doxycycline treatment reverted changes in calponin-1 expression. MMP-2 contributes to hypertrophic remodelling in aortas by decreasing calponin-1 levels, which may result in VSMC proliferation. On the other hand, MMP-2-dependent increased calponin-1 in mesenteric arteries may contribute to vascular hypercontractility in 2K-1C rats. Divergent regulation of calponin-1 by MMP-2 may be an important mechanism that leads to maladaptive vascular effects in hypertension.