Synthesis Of Matrix Proteins Research Articles

NLRP3 inflammasome activation contributes to the development of the pro-fibrotic phenotype of lung fibroblasts

Idiopathic pulmonary fibrosis (IPF) is an irreversible progressive interstitial lung disease of unknown cause. The poorly understood pathophysiology of IPF poses substantial challenges to the development of effective anti-lung fibrotic drugs. The NLRP3 inflammasome, a key component of the innate immune system, has recently been linked to the pathogenesis of lung fibrosis. However, the specific contributions of NLRP3 inflammasomes to determination of the pro-fibrotic phenotype of lung fibroblasts, which play a central role in the production of extracellular matrix protein, remain to be investigated. Therefore, the present study was performed to elucidate the involvement of NLRP3 inflammasome signalling pathways in modulation of lung fibroblast proliferation and differentiation. We found that activation of NLRP3 inflammasomes increased in lung fibroblasts derived from individuals with pulmonary fibrosis and in normal lung fibroblasts stimulated with transforming growth factor β and platelet-derived growth factor. Importantly, blockage of NLRP3 inflammasome signalling, either by gene silencing of NLRP3 or using pharmacological inhibitors of NLRP3, caspase-1, or IL-1 receptor, inhibited the proliferation, differentiation, and extracellular matrix protein synthesis of activated lung fibroblasts. Moreover, induction of the reactive oxygen species/thioredoxin-interacting protein axis, an upstream signalling pathway of NLRP3 inflammasomes, was essential for maintenance of the pro-fibrotic phenotype of lung fibroblasts. Interestingly, treatments with pharmacological inhibitors of NLRP3 inflammasomes prevented the progression of bleomycin-induced pulmonary fibrosis in mice. Collectively, these findings suggest that aberrant activation of NLRP3 inflammasomes is a critical event in the pathogenesis of IPF and that targeting NLRP3 inflammasomes may serve as a therapeutic strategy for IPF.

Coenzyme Q-10 reduced the aberrant production of extracellular matrix proteins in uterine leiomyomas through transforming growth factor beta 3

To evaluate the impact of coenzyme Q-10 (CoQ-10) on the dysregulated synthesis of extracellular matrix proteins mediated by transforming growth factor beta 3 (TGF-β3) in uterine leiomyomas. Laboratory study. University. None. Treatment of immortalized uterine myometrial and leiomyoma cells to TGF-β3 and CoQ-10. The protein concentrations of collagen 1A1 (COL1A1), collagen 3A1 (COL3A1), collagen 11A1 (COL11A1), and fibronectin (FN1) were assessed through western blot analysis after treatment of immortalized uterine myometrial and leiomyoma cells with both transforming growth factor beta (TGF-β) 3 and concentrations of CoQ-10 at 10, 50, and 100 μM concurrently for 24 hours. Immortalized uterine leiomyoma and myometrial cells exposed to TGF-β3 for 24 hours demonstrated a significant up-regulation of COL1A1, COL3A1, COL11A1, and FN1 compared with untreated cells. In leiomyoma cells, concurrent treatment with CoQ-10 over the same timeframe revealed a dose-dependent decrease in these protein concentrations compared with those in cells treated with TGF-β3 alone. At the highest concentration of 100 μM of CoQ-10, significant decreases in the amounts of COL1A1 (0.59 ± 0.10-fold), COL3A1 (0.46 ± 0.09-fold), COL11A1 (0.53 ± 0.09-fold), and FN1 (0.56 ± 0.09-fold) were observed. Similarly, myometrial cells exposed to both TGF-β3 and CoQ-10 demonstrated a dose-responsive decline in the amount of extracellular matrix protein compared with cells exposed to TGF-β3 alone. Significant reductions in the amounts of COL1A1 (0.75 ± 0.03-fold), COL3A1 (0.48 ± 0.06-fold), COL11A1 (0.38 ± 0.06), and FN1 (0.69 ± 0.04-fold) were appreciated at 100-μM CoQ-10. Coenzyme Q-10 mitigated the aberrant production of key biomarkers of the extracellular matrix mediated by TGF-β3 in uterine leiomyomas. Our findings highlight a promising nonhormonal compound that can counteract the fibroproliferative process inherent to leiomyomas.

Mechanical properties, collagen and glycosaminoglycan content of equine superficial digital flexor tendons are not affected by training.

Physical activity can activate extracellular matrix (ECM) protein synthesis and influence the size and mechanical properties of tendon. In this study, we aimed to investigate whether different training histories of horses would influence the synthesis of collagen and other matrix proteins and alter the mechanical properties of tendon. Samples from superficial digital flexor tendon (SDFT) from horses that were either (a) currently race trained (n = 5), (b) previously race trained (n = 5) or (c) untrained (n = 4) were analysed for matrix protein abundance (mass spectrometry), collagen and glycosaminoglycan (GAG) content, ECM gene expression and mechanical properties. It was found that ECM synthesis by tendon fibroblasts invitro varied depending upon the previous training history. In contrast, fascicle morphology, collagen and GAG content, mechanical properties and ECM gene expression of the tendon did not reveal any significant differences between groups. In conclusion, although we could not identify any direct impact of the physical training history on the mechanical properties or major ECM components of the tendon, it is evident that horse tendon cells are responsive to loading invivo, and the training background may lead to a modification in the composition of newly synthesised matrix.

Upregulation of the Urotensin II System in Diabetic Kidney Disease Includes Urotensin II-Related Peptide

The urotensin II (UII) system consists of endogenous ligands UII and its paralog urotensin II-related peptide (URP) and their receptor, UT. Originally isolated from the rat brain, URP is conserved across all vertebrates and shares the same cyclic hexapeptide core sequence with UII. However, UII and URP exhibit different N-terminal amino acid sequences. Beyond the central nervous system, UII and URP are functionally expressed in peripheral tissues. Alterations in tissue expression levels of UII and UT and blood or urinary UII concentrations have been associated with cardiovascular, pulmonary, and kidney dysfunctions, including hypertension, chronic heart failure, pulmonary hypertension, glomerulonephritis, and diabetes, making the UII system a potential therapeutic target for cardiovascular and kidney disease. The skeletal muscle and plasma levels of UII are increased in diabetic mice. Increased kidney tissue expression levels of UII and UT have also been demonstrated in humans and animals with diabetic kidney disease (DKD). Our recent work showed that UT is functionally expressed in cultured mouse glomerular mesangial cells (GMCs). Activation of UT by UII contributes to Ca2+-dependent GMC proliferation and extracellular matrix protein accumulation under high glucose conditions. We have also shown that DKD is attenuated in UT knockout mice. Despite the structural homology between UII and URP, studies have shown that the peptides may exhibit differential central and peripheral expression and pathophysiological function. However, whether URP is dysregulated in DKD remains unclear. Here, we examined whether URP production and kidney expression levels are altered in a hyperglycemic milieu and associated with DKD. Using a streptozotocin (STZ)-induced diabetes model, we examined the kidney tissue, plasma, and urinary levels of UII peptides. We also tested the hypothesis that, like UII, URP stimulates GMC proliferation and matrix protein synthesis. Our data show that protein and mRNA expression levels of both UII and URP were increased in the kidneys of hyperglycemic mice that developed albuminuria. Urinary and plasma UII and URP concentrations were also elevated in the mice. Although both UII and URP stimulated proliferation and type IV collagen production in cultured mouse GMCs by activating UT, the effect of UII was greater. Our data suggests that changes in the UII system in DKD are not limited to UII and UT but include the less-studied URP. GMC proliferation and extracellular matrix accumulation driven by UII and URP may contribute to DKD. NHLBI: R01 HL151735. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Consequences of Amyloid-β Deficiency for the Liver.

The hepatic content of amyloid beta (Aβ) decreases drastically in human and rodent cirrhosis highlighting the importance of understanding the consequences of Aβ deficiency in the liver. This is especially relevant in view of recent advances in anti-Aβ therapies for Alzheimer's disease (AD). Here, it is shown that partial hepatic loss of Aβ in transgenic AD mice immunized with Aβ antibody 3D6 and its absence in amyloid precursor protein (APP) knockout mice (APP-KO), as well as in human liver spheroids with APP knockdown upregulates classical hallmarks of fibrosis, smooth muscle alpha-actin, and collagen type I. Aβ absence in APP-KO and deficiency in immunized mice lead to strong activation of transforming growth factor-β (TGFβ), alpha secretases, NOTCH pathway, inflammation, decreased permeability of liver sinusoids, and epithelial-mesenchymal transition. Inversely, increased systemic and intrahepatic levels of Aβ42 in transgenic AD mice and neprilysin inhibitor LBQ657-treated wild-type mice protect the liver against carbon tetrachloride (CCl4)-induced injury. Transcriptomic analysis of CCl4-treated transgenic AD mouse livers uncovers the regulatory effects of Aβ42 on mitochondrial function, lipid metabolism, and its onco-suppressive effects accompanied by reduced synthesis of extracellular matrix proteins. Combined, these data reveal Aβ as an indispensable regulator of cell-cell interactions in healthy liver and a powerful protector against liver fibrosis.

Implanting mechanically reprogrammed fibroblasts for aged tissue regeneration and wound healing.

Cell-based therapies are essential for tissue regeneration and wound healing during aging. Autologous transplantation of aging cells is ineffective due to their increased senescence and reduced tissue remodeling capabilities. Alternatively, implanting reprogrammed aged cells provides unique opportunities. In this paper, we demonstrate the implantation of partially reprogrammed aged human dermal fibroblasts into invitro aged skin models for tissue regeneration and wound healing. The partially reprogrammed cells were obtained using our previously reported, highly efficient mechanical approach. Implanted cells showed enhanced expression of extracellular matrix proteins in the large area of aged tissue. In addition, the implanted cells at wound sites showed increased extracellular matrix protein synthesis and matrix alignment. Transcriptome analysis, combined with chromatin biomarkers, revealed these implanted cells upregulated tissue regeneration and wound healing pathways. Collectively our results provide a novel, nongenetic, partial reprogramming of aged cells for cell-based therapies in regenerative medicine.

The Unknown Role of Periostin in Psoriatic Epidermal Hyperplasia.

Psoriasis is an inflammatory skin disease that affects 1-2% of the general population. The pathomechanism is based on type 1 immunological reactions. Hyperplasia of the epidermis in psoriasis is a result of disrupted epidermal architecture due to increased synthesis and expression of extracellular matrix proteins. In our study, we analyzed the involvement of periostin (POSTN) in the pathogenesis of psoriasis, as one of the extracellular matrix proteins belonging to the fasciclin family. The study group consisted of 70 patients with psoriasis, while the control group comprised 30 healthy individuals. The serum concentrations of POSTN, Il-6, Il-17, Il-22, TNF-α and IFN-γ were measured in all participants. The severity of psoriasis was determined using the PASI (Psoriasis Area and Severity Index) score. The presence of POSTN in biopsy samples of 50 patients was assessed using the direct immunofluorescence method. The results were subjected to statistical analysis. The serum concentrations of POSTN, Il-6, Il-17, Il-22, TNF-α and IFN-γ in the study group are significantly higher than in the control group. Positive correlation has been demonstrated between the PASI score and the investigated cytokines, but not with POSTN. There was no statistically significant correlation between the POSTN level and the cytokines levels. POSTN deposits were localized in the epidermis in 66% of patients with psoriasis. The role of POSTN in the pathogenesis of psoriasis remains unclear. The mechanisms inducing the synthesis and expression of POSTN in psoriatic skin are not yet fully understood. Further research is needed to enhance our understanding of the mechanism underlying epidermal hyperplasia in psoriasis.

Survivin regulates intracellular stiffness and extracellular matrix production in vascular smooth muscle cells.

Vascular dysfunction is a common cause of cardiovascular diseases characterized by the narrowing and stiffening of arteries, such as atherosclerosis, restenosis, and hypertension. Arterial narrowing results from the aberrant proliferation of vascular smooth muscle cells (VSMCs) and their increased synthesis and deposition of extracellular matrix (ECM) proteins. These, in turn, are modulated by arterial stiffness, but the mechanism for this is not fully understood. We found that survivin is an important regulator of stiffness-mediated ECM synthesis and intracellular stiffness in VSMCs. Whole-transcriptome analysis and cell culture experiments showed that survivin expression is upregulated in injured femoral arteries in mice and in human VSMCs cultured on stiff fibronectin-coated hydrogels. Suppressed expression of survivin in human VSMCs significantly decreased the stiffness-mediated expression of ECM components related to arterial stiffening, such as collagen-I, fibronectin, and lysyl oxidase. By contrast, expression of these ECM proteins was rescued by ectopic expression of survivin in human VSMCs cultured on soft hydrogels. Interestingly, atomic force microscopy analysis showed that suppressed or ectopic expression of survivin decreases or increases intracellular stiffness, respectively. Furthermore, we observed that inhibiting Rac and Rho reduces survivin expression, elucidating a mechanical pathway connecting intracellular tension, mediated by Rac and Rho, to survivin induction. Finally, we found that survivin inhibition decreases FAK phosphorylation, indicating that survivin-dependent intracellular tension feeds back to maintain signaling through FAK. These findings suggest a novel mechanism by which survivin potentially modulates arterial stiffness.

The Crosstalk between Mesenchymal Stromal/Stem Cells and Hepatocytes in Homeostasis and under Stress.

Liver diseases, characterized by high morbidity and mortality, represent a substantial medical problem globally. The current therapeutic approaches are mainly aimed at reducing symptoms and slowing down the progression of the diseases. Organ transplantation remains the only effective treatment method in cases of severe liver pathology. In this regard, the development of new effective approaches aimed at stimulating liver regeneration, both by activation of the organ's own resources or by different therapeutic agents that trigger regeneration, does not cease to be relevant. To date, many systematic reviews and meta-analyses have been published confirming the effectiveness of mesenchymal stromal cell (MSC) transplantation in the treatment of liver diseases of various severities and etiologies. However, despite the successful use of MSCs in clinical practice and the promising therapeutic results in animal models of liver diseases, the mechanisms of their protective and regenerative action remain poorly understood. Specifically, data about the molecular agents produced by these cells and mediating their therapeutic action are fragmentary and often contradictory. Since MSCs or MSC-like cells are found in all tissues and organs, it is likely that many key intercellular interactions within the tissue niches are dependent on MSCs. In this context, it is essential to understand the mechanisms underlying communication between MSCs and differentiated parenchymal cells of each particular tissue. This is important both from the perspective of basic science and for the development of therapeutic approaches involving the modulation of the activity of resident MSCs. With regard to the liver, the research is concentrated on the intercommunication between MSCs and hepatocytes under normal conditions and during the development of the pathological process. The goals of this review were to identify the key factors mediating the crosstalk between MSCs and hepatocytes and determine the possible mechanisms of interaction of the two cell types under normal and stressful conditions. The analysis of the hepatocyte-MSC interaction showed that MSCs carry out chaperone-like functions, including the synthesis of the supportive extracellular matrix proteins; prevention of apoptosis, pyroptosis, and ferroptosis; support of regeneration; elimination of lipotoxicity and ER stress; promotion of antioxidant effects; and donation of mitochondria. The underlying mechanisms suggest very close interdependence, including even direct cytoplasm and organelle exchange.

Diagnostic and therapeutic potential of transforming growth factor beta 1 in solid organ transplantation: recent research findings

Federation Clinical outcomes of solid organ transplantation depend on many factors. One of the main factors is the risk of post-transplant complications, which affect allograft and recipient survival. Multifactorial organ damage in post-transplant complications and the search for diagnostic and prognostic indicators of the condition have contributed to the study and selection of a wide range of proteomic and molecular genetic biomarkers, which have shown to be effective in solid organ transplantation. The use of biomarkers opens up additional possibilities for assessing the risk of complications and their early diagnosis. This potentially reduces the frequency of invasive diagnostic procedures. Transforming growth factor beta 1 (TGF-β1) regulates many biological processes, has anti-inflammatory and immunosuppressive effects, participates in immune response, and plays a key role in extracellular matrix (ECM) protein synthesis. ECM dysregulation leads to fibroblast hyperproliferation and increased collagen synthesis and, consequently, tissue fibrosis. The variability of the diagnostic and prognostic potential of TGF-β1 has been demonstrated in studies on recipients of various solid organs. The objective of this review is to analyze recent evidence on the role of TGF-β1 in the development of post-transplant complications and to assess its prospects as a marker of graft pathology or as a target for therapy.

Uterine inflammation status modulates eggshell mineralization via calcium transport and matrix protein synthesis in laying hens.

This study explored the effects of uterine inflammation on eggshell mineralization, ultrastructure and mechanical properties in laying hens modified by a lipopolysaccharide (LPS) challenge or dietary essential oil (EO) addition. In trial 1, a total of 72 Hy-line Brown layers at 36wk of age were randomly assigned to 3 treatment groups (n=8), where they were intravenously injected with phosphate buffered saline, LPS at 1mg/kg body weight, or LPS 3 times at 24-h intervals. In trial 2, a total of 288 Hy-line Brown layers at 60wk of age were randomly divided into 4 groups (n=8), where they were fed basal diets supplemented with EO at 0, 50, 100 and 200mg/kg for 12wk. A uterine inflammation model was constructed with LPS treatment, indicated by the elevated expression of IL-1β and TNF-α (P<0.05) and lymphocyte infiltration. Uterine inflammation caused remarkable decreases in eggshell thickness and mechanical properties with structure deteriorations (P<0.05). Uterine inflammation stimulated the expression of matrix proteins ovotransferrin (TF) and ovalbumin (OVAL), while depressing the mRNA levels of calbindin-1 (CALB1) and osteopontin in uterine mucosa (P<0.05). In contrast, EO addition alleviated uterine inflammation, evidenced by depressed levels of IL-1β and IL-6 (P<0.05). There was a significant elevation in shell thickness and breaking strength following EO intervention (P<0.05), and these effects were maximized at addition of 100mg/kg. Further, EO improved shell ultrastructure including more early fusion, less type B mammillae, and increased effective thickness (P<0.05). The alleviated inflammation decreased the expression of OVAL and TF, whereas ion transport genes like CALB1 and solute carrier family 26 member 9 were upregulated (P<0.05). Our findings suggest that inflammatory status can impact uterine functions in calcium transport and the synthesis of matrix proteins especially such as OVAL and TF, which in turn modulates calcium precipitation and ultrastructure formation, thereby determining eggshell mechanical properties. These findings provide a novel insight into the uterine inflammation-mediated modifications of eggshell quality.

Blood-derived biomaterials for tissue graft biofabrication by solvent-based extrusion bioprinting

This article provides an overview of the different types of blood-derived biomaterials that can be used as solvent additives in the formulation of inks/bioinks for use in solvent extrusion printing/bioprinting. We discuss the properties of various blood sub-products obtained after blood fractionation in terms of their use in tailoring ink/bioink to produce functional constructs designed to improve tissue repair. Blood-derived additives include platelets and/or their secretome, including signaling proteins and microvesicles, which can drive cell migration, inflammation, angiogenesis, and synthesis of extracellular matrix proteins. The contribution of plasma to ink/bioink functionalization relies not only on growth factors, such as hepatocyte growth factor and insulin growth factors, but also on adhesive proteins, such as fibrinogen/fibrin, vitronectin, and fibronectin. We review the current developments and progress in solvent-based extrusion printing/bioprinting with inks/bioinks functionalized with different blood-derived products, leading toward the development of more advanced patient-specific 3D constructs in multiple medical fields, including but not limited to oral tissues and cartilage, bone, skin, liver, and neural tissues. This information will assist researchers in identifying the most suitable blood-derived product for their ink/bioink formulation based on the intended regenerative functionality of the target tissue.

Sirt1 protects against intervertebral disc degeneration induced by 1,25-dihydroxyvitamin D insufficiency in mice by inhibiting the NF-κB inflammatory pathway.

It has been demonstrated that vitamin D deficiency is associated with an increased risk of patients developing lumbar disc herniation. However, intervertebral disc degeneration caused by active vitamin D deficiency has not been reported. Thus, the purpose of this study was to e investigate the role and mechanism of 1,25-dihydroxyvitamin D (1,25(OH)2D) insufficiency in promoting intervertebral disc degeneration. The phenotypes of intervertebral discs were compared in wild-type mice and mice with heterozygous deletion of 1α-hydroxylase [1α(OH)ase+/-] at 8 mouths of age using iconography, histology and molecular biology. A mouse model that overexpressed Sirt1 in mesenchymal stem cells on a 1α(OH)ase+/- background (Sirt1Tg/1α(OH)ase+/-) was generated by crossing Prx1-Sirt1 transgenic mice with 1α(OH)ase+/- mice and comparing their intervertebral disc phenotypes with those of Sirt1Tg, 1α(OH)ase+/- and wild-type littermates at 8 months of age. A vitamin D receptor (VDR)-deficient cellular model was generated by knock-down of endogenous VDR using Ad-siVDR transfection into nucleus pulposus cells; VDR-deficient nucleus pulposus cells were then treated with or without resveratrol. The interactions between Sirt1 and acetylated p65, and p65 nuclear localization, were examined using co-immunoprecipitation, Western blots and immunofluorescence staining. VDR-deficient nucleus pulposus cells were also treated with 1,25(OH)2D3, or resveratrol or 1,25(OH)2D3 plus Ex527 (an inhibitor of Sirt1). Effects on Sirt1 expression, cell proliferation, cell senescence, extracellular matrix protein synthesis and degradation, nuclear factor-κB (NF-κB), and expression of inflammatory molecules, were examined, using immunofluorescence staining, Western blots and real-time RT-PCR. 1,25(OH)2D insufficiency accelerated intervertebral disc degeneration by reducing extracellular matrix protein synthesis and enhancing extracellular matrix protein degradation with reduced Sirt1 expression in nucleus pulposus tissues. Overexpression of Sirt1 in MSCs protected against 1,25(OH)2D deficiency-induced intervertebral disc degeneration by decreasing acetylation and phosphorylation of p65 and inhibiting the NF-κB inflammatory pathway. VDR or resveratrol activated Sirt1 to deacetylate p65 and inhibit its nuclear translocation into nucleus pulposus cells. Knockdown of VDR decreased VDR expression and significantly reduced the proliferation and extracellular matrix protein synthesis of nucleus pulposus cells, significantly increased the senescence of nucleus pulposus cells and significantly downregulated Sirt1 expression, and upregulated matrix metallopeptidase 13 (MMP13), tumor necrosis factor-α (TNF-α) and interleukin 1β (IL-1β) expression; the ratios of acetylated and phosphorylated p65/p65 in nucleus pulposus cells were also increased. Treatment of nucleus pulposus cells with VDR reduction using 1,25(OH)2D3 or resveratrol partially rescued the degeneration phenotypes, by up-regulating Sirt1 expression and inhibiting NF-κB inflammatory pathway; these effects in nucleus pulposus cells were blocked by inhibition of Sirt1. Results from this study indicate that the 1,25(OH)2D/VDR pathway can prevent the degeneration of nucleus pulposus cells by inhibiting the NF-κB inflammatory pathway mediated by Sirt1.The Translational Potential of This Article: This study provides new insights into the use of 1,25(OH)2D3 to prevent and treat intervertebral disc degeneration caused by vitamin D deficiency.

Modulating tumor-stromal crosstalk via a redox-responsive nanomedicine for combination tumor therapy.

Interaction between carcinoma-associated fibroblasts (CAFs) and tumor cells leads to the invasion and metastasis of breast cancer. Herein, we prepared a redox-responsive chondroitin sulfate (CS)-based nanomedicine, in which hydrophobic cabazitaxel (CTX) was conjugated to the backbone of CS via glutathione (GSH)-sensitive dithiomaleimide (DTM) to form an amphipathic CS-DTM-CTX (CDC) conjugate, and dasatinib (DAS) co-assembled with the CDC conjugate to obtain DAS@CDC. After CD44 receptor-mediated internalization by CAFs, the nanomedicine could reverse CAFs to normal fibroblasts, blocking their crosstalk with tumor cells and reducing synthesis of major tumor extracellular matrix proteins, including collagen and fibronectin. Meanwhile, the nanomedicine internalized by tumor cells could effectively inhibit tumor proliferation and metastasis, leading to shrinkage of the tumor volume and inhibition of lung metastasis in a subcutaneous 4 T1 tumor model with low side effects. Collectively, the nanomedicine showed a remarkably synergistic therapy effect against breast cancer by modulating tumor-stromal crosstalk.

Changes in the Mechanical Properties of Fast and Slow Skeletal Muscle after 7 and 21 Days of Restricted Activity in Rats.

Disuse muscle atrophy is usually accompanied by changes in skeletal muscle structure, signaling, and contractile potential. Different models of muscle unloading can provide valuable information, but the protocols of experiments with complete immobilization are not physiologically representative of a sedentary lifestyle, which is highly prevalent among humans now. In the current study, we investigated the potential effects of restricted activity on the mechanical characteristics of rat postural (soleus) and locomotor (extensor digitorum longus, EDL) muscles. The restricted-activity rats were kept in small Plexiglas cages (17.0 × 9.6 × 13.0 cm) for 7 and 21 days. After this, soleus and EDL muscles were collected for ex vivo mechanical measurements and biochemical analysis. We demonstrated that while a 21-day movement restriction affected the weight of both muscles, in soleus muscle we observed a greater decrease. The maximum isometric force and passive tension in both muscles also significantly changed after 21 days of movement restriction, along with a decrease in the level of collagen 1 and 3 mRNA expression. Furthermore, the collagen content itself changed only in soleus after 7 and 21 days of movement restriction. With regard to cytoskeletal proteins, in our experiment we observed a significant decrease in telethonin in soleus, and a similar decrease in desmin and telethonin in EDL. We also observed a shift towards fast-type myosin heavy chain expression in soleus, but not in EDL. In summary, in this study we showed that movement restriction leads to profound specific changes in the mechanical properties of fast and slow skeletal muscles. Future studies may include evaluation of signaling mechanisms regulating the synthesis, degradation, and mRNA expression of the extracellular matrix and scaffold proteins of myofibers.

Neddylation of EphB1 Regulates Its Activity and Associates with Liver Fibrosis

Liver fibrosis is a pathological process characterized by the excessive synthesis and accumulation of extracellular matrix proteins (ECMs) contributed mainly by the activated hepatic stellate cells (HSCs). Currently, no direct and effective anti-fibrotic agents have been approved for clinical use worldwide. Although the dysregulation of Eph receptor tyrosine kinase EphB2 has been reported to associate with the development of liver fibrosis, the involvement of other Eph family members in liver fibrosis remains underexplored. In this study, we found that the expression of EphB1 is significantly increased accompanying remarkable neddylation in activated HSCs. Mechanistically, this neddylation enhanced the kinase activity of EphB1 by the prevention of its degradation, thereby promoting the proliferation, migration, and activation of HSCs. Our findings revealed the involvement of EphB1 in the development of liver fibrosis through its neddylation, which provides new insights into the Eph receptor signaling and a potential target for the treatment of liver fibrosis.

Survivin regulates intracellular stiffness and extracellular matrix production in vascular smooth muscle cells.

Vascular dysfunction is a common cause of cardiovascular diseases characterized by the narrowing and stiffening of arteries. Arterial narrowing results from the aberrant proliferation of vascular smooth muscle cells (VSMCs) and their increased synthesis and deposition of extracellular matrix (ECM) proteins. These, in turn, are modulated by arterial stiffness, but the mechanism for this is not fully understood. We found that survivin (an inhibitor of apoptosis) is an important regulator of stiffness-mediated ECM synthesis and intracellular stiffness in VSMCs. Whole-transcriptome analysis and cell culture experiments showed that survivin expression is upregulated in injured femoral arteries in mice and in human VSMCs cultured on stiff fibronectin-coated hydrogels. Suppressed expression of survivin in human VSMCs and mouse embryonic fibroblasts decreased the stiffness-mediated expression of ECM components implicated in arterial stiffness, namely, collagen-I, fibronectin, and lysyl oxidase. By contrast, expression of these proteins was upregulated by the overexpression of survivin in human VSMCs cultured on soft hydrogels. Atomic force microscopy analysis showed that suppressed or enhanced expression of survivin decreases or increases intracellular stiffness, respectively. These findings suggest a novel mechanism by which survivin modulates arterial stiffness.

1,25-Dihydroxyvitamin D Deficiency Accelerates Aging-related Osteoarthritis via Downregulation of Sirt1 in Mice.

Emerging observational data suggest that vitamin D deficiency is associated with the onset and progression of knee osteoarthritis (OA). However, the relationship between vitamin D level and OA and the role of vitamin D supplementation in the prevention of knee OA are controversial. To address these issues, we analyzed the articular cartilage phenotype of 6- and 12-month-old wild-type and 1α(OH)ase-/- mice and found that 1,25(OH)2D deficiency accelerated the development of age-related spontaneous knee OA, including cartilage surface destruction, cartilage erosion, proteoglycan loss and cytopenia, increased OARSI score, collagen X and Mmp13 positive chondrocytes, and increased chondrocyte senescence with senescence-associated secretory phenotype (SASP). 1,25(OH)2D3 supplementation rescued all knee OA phenotypes of 1α(OH)ase-/- mice in vivo, and 1,25(OH)2D3 rescued IL-1β-induced chondrocyte OA phenotypes in vitro, including decreased chondrocyte proliferation and cartilage matrix protein synthesis, and increased oxidative stress and cell senescence. We also demonstrated that VDR was expressed in mouse articular chondrocytes, and that VDR knockout mice exhibited knee OA phenotypes. Furthermore, we demonstrated that the down-regulation of Sirt1 in articular chondrocytes of 1α(OH)ase-/- mice was corrected by supplementing 1,25(OH)2D3 or overexpression of Sirt1 in mesenchymal stem cells (MSCs) and 1,25(OH)2D3 up-regulated Sirt1 through VDR mediated transcription. Finally, we demonstrated that overexpression of Sirt1 in MSCs rescued knee OA phenotypes in 1α(OH)ase-/- mice. Thus, we conclude that 1,25(OH)2D3, via VDR-mediated gene transcription, plays a key role in preventing the onset of aging-related knee OA in mouse models by up-regulating Sirt1, an aging-related gene that promotes articular chondrocyte proliferation and extracellular matrix protein synthesis, and inhibits senescence and SASP.

Tenocytes do not just lie in a vacuum: the role of lipids, glycemic metabolism and thyroid hormones in tendinopathy and tendon rupture. A narrative review

Purpose: Tendinopathies and tendon ruptures are a common cause of pain and disabilities. The pathogenesis is considered multifactorial, and currently described as the failed healing response. Traditionally, tendon injuries have been mostly referred to age, overuse or mechanical factors. Recently, some authors have focused their attention on the influence of metabolic diseases and hormones on tendon homeostasis, opening new perspectives. There are even more studies which show how systemic condition and pathologies are able to influence the proliferation of tenocytes, the synthesis of extracellular matrix proteins, and the organization and properties of the extra cellular matrix of the tendons. Methods: In this article, we reviewed the current knowledge about the influence of lipids, glucose and thyroid hormones on the pathogenesis of tendinopathy. Results: Beside the traditional extrinsic and mechanical risk factors, this article showed the importance of metabolism and hormones of tendon health, reinforcing the idea of their great influence on the pathogenesis of tendinopathy. Current literature indicates that hypercholesterolemia, obesity, diabetes mellitus and hypothyroidism are all risk factors for tendinopathies and tendon ruptures. Conclusions: The precise role of each predisposing factor remains incompletely understood, and further epidemiology and laboratory studies should be performed to establish the strength of the association with tendon pathologies and their pathogenetic mechanism. Keywords: inertial measurement unit; acceleration; max speed; metrics; team sports.

Effect of recombinant Sox9 protein on the expression of cartilage-specific genes in human dermal fibroblasts cell culture

Introduction: Damage to the hyaline layer of large joints resulting from injuries or age-related changes restricts their mobility. The repair of these disorders is an actual issue in medicine. One of the promising therapies is the usage of cell engineering constructs based on a biodegradable scaffold and a modified cell culture. A frequently used method to modify the proliferation of cell culture for tissue engineering of hyaline cartilage, which makes it possible to introduce an experimental technique into clinical practice, is the application of recombinant proteins that affect chondrogenesis and lead to increase synthesis of extracellular matrix proteins. The goal of this work was to elucidate the effect of the key transcription factor in the chondrogenesis process – Sox9 protein – on the expression of genes responsible for chondrogenesis (Tgfβ3, Sox9, Acan, Comp, Col2a1).&#x0D; Materials and methods: Human dermal fibroblasts were used as a cell culture; recombinant Sox9 was added at each change of medium; the modification was carried out for 21 days, and difference in gene expression was determined by real-time PCR and -ΔΔCt method.&#x0D; Results and discussion: To assess the effectiveness of fibroblast modification, we analyzed the changing of expression of genes responsible for chondrogenesis (Tgfß3, Sox9, Col2a1, Acan, Comp). We studied the direct effect of different concentrations of the recombinant Sox9 protein on the proliferation of dermal fibroblasts in the chondrogenic direction. We showed that the addition of the recombinant Sox9 protein in various concentration did not significantly change the expression of both the genes encoding proteins of the extracellular matrix of hyaline cartilage (Acan, Col2a1, Comp) and the genes encoding chondrogenesis inducers (Tgfß3, Sox9).&#x0D; Conclusion: As a result of the experiments, it was shown that the recombinant Sox9 protein has practically no effect on chondrogenic differentiation and does not significantly change the expression of chondrogenesis genes.