Changes in biological behaviors of rat dermal fibroblasts induced by high expression of MMP9

Glucagon-like peptide-1: a multi-faceted anti-inflammatory agent

Inflammation contributes to many chronic conditions. It is often associated with circulating pro-inflammatory cytokines and immune cells. GLP-1 levels correlate with disease severity. They are often elevated and can serve as markers of inflammation. Previous studies have shown that oxytocin, hCG, ghrelin, alpha-MSH and ACTH have receptor-mediated anti-inflammatory properties that can rescue cells from damage and death. These peptides have been studied well in the past century. In contrast, GLP-1 and its anti-inflammatory properties have been recognized only recently. GLP-1 has been proven to be a useful adjuvant therapy in type-2 diabetes mellitus, metabolic syndrome, and hyperglycemia. It also lowers HbA1C and protects cells of the cardiovascular and nervous systems by reducing inflammation and apoptosis. In this review we have explored the link between GLP-1, inflammation, and sepsis.

Engineered barriers regulate osteoblast cell migration in vertical direction

Considering cell migration is essential for understanding physiological processes and diseases. The vertical migration of cells in three dimensions is vital, but most previous studies on cell migration have only focused on two-dimensional horizontal migration. In this paper, cell migration in the vertical direction was studied. Barriers with a height of 1, 5, 10, and 25 µm with grating and arrows in channels as guiding patterns were fabricated. The effects of barrier height and guiding patterns on the vertical migration of MC3T3 cells were explored. The study revealed that taller barriers hinder vertical migration of MC3T3 cells, whereas grating and arrows in channels promote it. The time-lapse and micrograph images showed that as the barrier height increased, the cell climbing angle along the barrier sidewall decreased, and the time taken to climb over the barrier increased. These results indicate that taller barriers increase the difficulty of vertical migration by MC3T3 cells. To promote the vertical migration of MC3T3 cells, 10 µm tall barriers with 18° and 40° sloped sidewalls were fabricated. For barriers with 18° sloped sidewalls, the probability for MC3T3 cells to climb up and down the 10 µm tall barriers was 40.6% and 20.3%, respectively; this is much higher than the migration probability over vertical barriers. This study shows topographic guidance on the vertical migration of MC3T3 cells and broadens the understanding of cell migration in the vertical direction.

Comprehensive Analysis of the Systemic Transcriptomic Alternations and Inflammatory Response during the Occurrence and Progress of COVID-19

The pandemic of the coronavirus disease 2019 (COVID-19) has posed huge threats to healthcare systems and the global economy. However, the host response towards COVID-19 on the molecular and cellular levels still lacks full understanding and effective therapies are in urgent need. Here, we integrate three datasets, GSE152641, GSE161777, and GSE157103. Compared to healthy people, 314 differentially expressed genes were identified, which were mostly involved in neutrophil degranulation and cell division. The protein-protein network was established and two significant subsets were filtered by MCODE: ssGSEA and CIBERSORT, which comprehensively revealed the alternation of immune cell abundance. Weighted gene coexpression network analysis (WGCNA) as well as GO and KEGG analyses unveiled the role of neutrophils and T cells during the progress of the disease. Based on the hospital-free days after 45 days of follow-up and statistical methods such as nonnegative matrix factorization (NMF), submap, and linear correlation analysis, 31 genes were regarded as the signature of the peripheral blood of COVID-19. Various immune cells were identified to be related to the prognosis of the patients. Drugs were predicted for the genes in the signature by DGIdb. Overall, our study comprehensively revealed the relationship between the inflammatory response and the disease course, which provided strategies for the treatment of COVID-19.

Transformation of fibroblast-like synoviocytes in rheumatoid arthritis; from a friend to foe

Swelling and the progressive destruction of articular cartilage are major characteristics of rheumatoid arthritis (RA), a systemic autoimmune disease that directly affects the synovial joints and often causes severe disability in the affected positions. Recent studies have shown that type B synoviocytes, which are also called fibroblast-like synoviocytes (FLSs), as the most commonly and chiefly resident cells, play a crucial role in early-onset and disease progression by producing various mediators. During the pathogenesis of RA, the FLSs' phenotype is altered, and represent invasive behavior similar to that observed in tumor conditions. Modified and stressful microenvironment by FLSs leads to the recruitment of other immune cells and, eventually, pannus formation. The origins of this cancerous phenotype stem fundamentally from the significant metabolic changes in glucose, lipids, and oxygen metabolism pathways. Moreover, the genetic abnormalities and epigenetic alterations have recently been implicated in cancer-like behaviors of RA FLSs. In this review, we will focus on the mechanisms underlying the transformation of FLSs to a cancer-like phenotype during RA. A comprehensive understanding of these mechanisms may lead to devising more effective and targeted treatment strategies.

The HIV protease inhibitor Saquinavir attenuates sepsis-induced acute lung injury and promotes M2 macrophage polarization via targeting matrix metalloproteinase-9

Imbalance of macrophage polarization plays an indispensable role in acute lung injury (ALI), which is considered as a promising target. Matrix metalloproteinase-9 (MMP-9) is expressed in the macrophage, and has a pivotal role in secreting inflammatory cytokines. We reported that saquinavir (SQV), a first-generation human immunodeficiency virus-protease inhibitor, restricted exaggerated inflammatory response. However, whether MMP-9 could regulate macrophage polarization and inhibit by SQV is still unknown. We focused on the important role of macrophage polarization in CLP (cecal ligation puncture)-mediated ALI and determined the ability of SQV to maintain M2 over M1 phenotype partially through the inhibition of MMP-9. We also performed a limited clinical study to determine if MMP-9 is a biomarker of sepsis. Lipopolysaccharide (LPS) increased MMP-9 expression and recombinant MMP-9 (rMMP-9) exacerbated LPS-mediated M1 switching. Small interfering RNA to MMP-9 inhibited LPS-mediated M1 phenotype and SQV inhibition of this switching was reversed with rMMP-9, suggesting an important role for MMP-9 in mediating LPS-induced M1 phenotype. MMP-9 messenger RNA levels in peripheral blood mononuclear cells of these 14 patients correlated with their clinical assessment. There was a significant dose-dependent decrease in mortality and ALI after CLP with SQV. SQV significantly inhibited LPS-mediated M1 phenotype and increased M2 phenotype in cultured RAW 264.7 and primary murine bone marrow-derived macrophages as well as lung macrophages from CLP-treated mice. This study supports an important role for MMP-9 in macrophage phenotypic switching and suggests that SQV-mediated inhibition of MMP-9 may be involved in suppressing ALI during systemic sepsis.

Directed vertical cell migration via bifunctionalized nanomaterials in 3D step-gradient nanocomposite hydrogels

Step-gradient scaffolds promote healthy cell migration, while inhibit the migration of cancerous cells in the XZ plane of the ²GradNS.

Cellular Senescence as the Pathogenic Hub of Diabetes-Related Wound Chronicity

Diabetes is constantly increasing at a rate that outpaces genetic variation and approaches to pandemic magnitude. Skin cells physiology and the cutaneous healing response are progressively undermined in diabetes which predisposes to lower limb ulceration, recidivism, and subsequent lower extremities amputation as a frightened complication. The molecular operators whereby diabetes reduces tissues resilience and hampers the repair mechanisms remain elusive. We have accrued the notion that diabetic environment embraces preconditioning factors that definitively propel premature cellular senescence, and that ulcer cells senescence impair the healing response. Hyperglycemia/oxidative stress/mitochondrial and DNA damage may act as major drivers sculpturing the senescent phenotype. We review here historical and recent evidences that substantiate the hypothesis that diabetic foot ulcers healing trajectory, is definitively impinged by a self-expanding and self-perpetuative senescent cells society that drives wound chronicity. This society may be fostered by a diabetic archetypal secretome that induces replicative senescence in dermal fibroblasts, endothelial cells, and keratinocytes. Mesenchymal stem cells are also susceptible to major diabetic senescence drivers, which accounts for the inability of these cells to appropriately assist in diabetics wound healing. Thus, the use of autologous stem cells has not translated in significant clinical outcomes. Novel and multifaceted therapeutic approaches are required to pharmacologically mitigate the diabetic cellular senescence operators and reduce the secondary multi-organs complications. The senescent cells society and its adjunctive secretome could be an ideal local target to manipulate diabetic ulcers and prevent wound chronification and acute recidivism. This futuristic goal demands harnessing the diabetic wound chronicity epigenomic signature.

Anti-inflammatory and pro-healing impacts of exendin-4 treatment in Zucker diabetic rats: Effects on skin wound fibroblasts

Using male Zucker diabetic fatty (ZDF) rats implanted subcutaneously with polyethylene mesh pieces stimulating granulation tissue development, we investigated the effects of the in vivo and in vitro treatment with exendin-4, a glucagon-like peptide-1 agonist displaying a variety of antidiabetic actions, on the markers of metabolism, inflammation, and healing in addition to skin wound fibroblast/myofibroblast activities. Exendin-4 at increasing doses of 3-10 μg/kg or 0.9% saline was injected daily to ZDF rats pre-implanted with the mesh for 3 weeks. Then, fibroblasts/myofibroblasts isolated from the granulation tissue in both groups were further exposed in vitro to exendin-4 at concentrations of 0-100 nmol/l. After a 3-week administration period, cumulative food and water intake and body weight were reduced significantly. The serum and fibroblast culture medium C-reactive protein (CRP) concentrations and matrix metalloprotease-9/tissue matrix metalloproteinase inhibitor-1 (MMP-9/TIMP-1) ratio in the fibroblast culture medium were diminished significantly in the exendin-4 pretreated group, indicating the increased expression of anti-inflammatory and pro-healing biomarkers. In vivo exendin-4 treatment also increased the number of living fibroblasts/myofibroblasts in cell cultures. The subsequent in vitro exposure to exendin-4 significantly increased metabolic activity and total collagen content in fibroblast/myofibroblast colonies derived from exendin-4-pretreated rats but reduced the number of viable cells. A cytotoxic effect was noted at the highest exendin-4 concentrations used. To conclude, the treatment of diabetic rats with exendin-4 had beneficial effects on systemic and tissue metabolic, inflammatory, and healing markers and on fibroblast functions crucial for wound repair but showed some cytotoxicity on these cells.

Immuno-modulatory effect of local rhEGF treatment during tissue repair in diabetic ulcers

Wound healing is a complex process that can be severely impaired due to pathological situations such as diabetes mellitus. Diabetic foot ulcers are a common complication of this pathology and are characterized by an excessive inflammatory response. In this work, the effects of local treatment with recombinant human epidermal growth factor (rhEGF) were studied using a full-thickness wound healing model in streptozotocin-induced diabetic rats. Wound healing process was assessed with different concentrations of rhEGF (0.1, 0.5, 2.0 and 8.0 µg/mL), placebo and both diabetic and non-diabetic controls (n = 53). The macroscopic healing observed in treated diabetic rats was affected by rhEGF concentration. Histologically, we also observed an improvement in the epithelialization, granulation tissue formation and maturation in treated groups, finding again the best response at doses of 0.5 and 2.0 µg/mL. Afterwards, the tissue immune response over time was assessed in diabetic rats using the most effective concentrations of rhEGF (0.5 and 2.0 µg/mL), compared to controls. The presence of macrophages, CD4⁺ T lymphocytes and CD8⁺ T lymphocytes, in the reparative tissue was quantified, and cytokine expression was measured by quantitative real-time PCR. rhEGF treatment caused a reduction in the number of infiltrating macrophages in the healing tissue of diabetic, as well as diminished activation of these leukocytes. These findings show that local administration of rhEGF improves the healing process of excisional wounds and the quality of the neoformed tissue in a dose-dependent manner. Besides, this treatment reduces the local inflammation associated with diabetic healing, indicating immuno-modulatory properties.

Regulation function of MMP-1 downregulated by siRNA on migration of heat-denatured dermal fibroblasts

Cutaneous wound healing is a complex physiological process that requires the efforts of various cell types and signaling pathways and often results in thickened collagen-enriched healed tissue called a scar. Therefore, the identification of the mechanism of cutaneous wound healing is necessary and has great value in providing better treatment. Here, we demonstrated that MMP-1 inhibition could promote cell proliferation in dermal fibroblasts via the MTT assay. Meanwhile, we investigated cell migration by flow cytometry and tested type I collagenase activity. We found that MMP-1 inhibition promoted cell proliferation and inhibited cell migration and type I collagenase activity. In conclusion, our study demonstrated that MMP-1 might be a potential therapeutic target in cutaneous wound healing.

Preparation of chitosan-collagen-alginate composite dressing and its promoting effects on wound healing

The present study aimed to prepare a composite dressing composed of collagen, chitosan, and alginate, which may promote wound healing and prevent from seawater immersion. Chitosan-collagen-alginate (CCA) cushion was prepared by paintcoat and freeze-drying, and it was attached to a polyurethane to compose CCA composite dressing. The swelling, porosity, degradation, and mechanical properties of CCA cushion were evaluated. The effects on wound healing and seawater prevention of CCA composite dressing were tested by rat wound model. Preliminary biosecurity was tested by cytotoxicity and hemocompatibility. The results revealed that CCA cushion had good water absorption and mechanical properties. A higher wound healing ratio was observed in CCA composite dressing treated rats than in gauze or chitosan treated ones. On the fifth day, the healing rates of CCA composite dressing, gauze, and chitosan were 48.49%±1.07%, 28.02%±6.4%, and 38.97%±8.53%, respectively. More fibroblast and intact re-epithelialization were observed in histological images of CCA composite dressing treated rats, and the expressions of EGF, bFGF, TGF-β, and CD31 increased significantly. CCA composite dressing showed no significant cytotoxicity, and favorable hemocompatibility. These results suggested that CCA composite dressing could prevent against seawater immersion and promote wound healing while having a good biosecurity.

Fibroblast-like synoviocyte metabolism in the pathogenesis of rheumatoid arthritis

An increasing number of studies show how changes in intracellular metabolic pathways alter tumor and immune cell function. However, little information about metabolic changes in other cell types, including synovial fibroblasts, is available. In rheumatoid arthritis (RA), fibroblast-like synoviocytes (FLS) are the most common cell type at the pannus–cartilage junction and contribute to joint destruction through their production of cytokines, chemokines, and matrix-degrading molecules and by migrating and invading joint cartilage. In this review, we show that these cells differ from healthy synovial fibroblasts, not only in their marker expression, proto-oncogene expression, or their epigenetic changes, but also in their intracellular metabolism. These metabolic changes must occur due to the stressful microenvironment of inflamed tissues, where concentrations of crucial nutrients such as glucose, glutamine, and oxygen are spatially and temporally heterogeneous. In addition, these metabolic changes will increase metabolite exchange between fibroblast and other synovial cells, which can potentially be activated. Glucose and phospholipid metabolism as well as bioactive lipids, including sphingosine-1-phosphate and lysophosphatidic acid, among others, are involved in FLS activation. These metabolic changes likely contribute to FLS involvement in aspects of immune response initiation or abnormal immune responses and strongly contribute to joint destruction.

Regulation of matrix metalloproteinase-2 and -9 during healing of dermal wounds after incision using radiofrequency energy in neonatal and adult rats

BACKGROUND

Radiofrequency energy (RFE) has many medical applications in the treatment of adults and children. The impact of RFE on healing-regulation systems in the developing tissues is not fully known. Matrix metalloproteinases (MMPs) are involved in the remodeling of the extracellular matrix and the inflammatory processes. MMPs are regulated differently among the different age groups. We evaluated possible changes in MMP activity after an incisional wound using a radiofrequency scalpel in neonatal and adult rats.

METHODS

In 30 Wistar rats [15 4-day-old (neonates) and 15 4-month-old (adults) rats], a ventral wound was created using a radiofrequency scalpel. Wounded areas and non-wounded tissues were harvested one, three and seven days after the intervention. Enzymatic activities of MMP-2 and MMP-9 were evaluated using gelatin zymography.

RESULTS

Adults expressed higher activity than neonates for MMP-2 on day 7 (Mann -Whitney U-test, p =0.009) and for MMP-9 on days one (p =0.005) and three (p =0.005). MMP-9 was expressed in higher amounts in the wounded tissue in comparison with non-wounded tissue during days one and three (Wilcoxon signed rank test, p =0.028 and p =0.043, respectively). MMP-2 was produced in equal amounts in the wounded and non-wounded tissue at all time-points. Only in the adult wounds at day seven, higher activity was noted compared with non-wounded skin (Wilcoxon signed rank test, p=0.043).

CONCLUSIONS

RFE, despite its local burning effect, does not interfere with known patterns of MMP regulation. Neonates have lower activity of MMPs than adults. Energy conduction through adjacent non-wounded tissues does not have an impact upon MMP regulation. HIPPOKRATIA 2017, 21(1): 85-92.

The effect of local hyperglycemia on skin cells in vitro and on wound healing in euglycemic rats

BACKGROUND

Multiple previous studies have established that high systemic blood glucose concentration impairs skin wound healing. However, the effects of local hyperglycemia on wound healing are not well defined. Comprehensive animal studies and in vitro studies using both fibroblasts and keratinocytes are lacking.

MATERIALS AND METHODS

Primary keratinocytes and fibroblasts were isolated from discarded human tissue, cultured under different concentrations of glucose, and the effect on cell function was examined. In addition, a rat full-thickness wound model was used to topically treat the wounds with different glucose concentrations and the effect on wound closure and re-epithelialization was investigated over time.

RESULTS

The cell viability experiments indicated that both keratinocytes and fibroblasts endure high glucose well and concentrations under 26 mM did not have a remarkable effect on their viability over time. Moderate addition of glucose (10 mM) boosted fibroblast proliferation (6-fold) but did not have an effect on keratinocyte proliferation. In both keratinocytes and fibroblasts, glucose inhibited their migration and already the addition of 5.6-mM glucose had an inhibitory effect. In vivo experiments showed that full-thickness wounds treated with topical glucose had impaired wound closure and lower re-epithelialization rate in comparison to nontreated control wounds. The results also showed that higher glucose concentrations inhibited wound healing more efficiently.

CONCLUSIONS

In conclusion, our study indicates that high glucose inhibits both keratinocyte and fibroblast migration as well as wound healing in vivo in a concentration dependent manner.

Peptide Regulation of Skin Fibroblast Functions during Their Aging In Vitro

The effect peptides KE, KED, AED and AEDG on proliferation (Ki-67), regeneration and aging (CD98hc), apoptosis (caspase-3), and extracellular matrix remodeling (MMP-9) in skin fibroblasts during their aging in culture were studied by immunofluorescent confocal microscopy. All studied peptides inhibited MMP-9 synthesis that increases during aging of skin fibroblasts and enhanced the expression of Ki-67 and CD98hc that are less intensively synthesized during cell aging. Peptides AED and AEDG suppressed caspase-dependent apoptosis that increases during aging of cell cultures.

Alterations of Dermal Connective Tissue Collagen in Diabetes: Molecular Basis of Aged-Appearing Skin

Alterations of the collagen, the major structural protein in skin, contribute significantly to human skin connective tissue aging. As aged-appearing skin is more common in diabetes, here we investigated the molecular basis of aged-appearing skin in diabetes. Among all known human matrix metalloproteinases (MMPs), diabetic skin shows elevated levels of MMP-1 and MMP-2. Laser capture microdissection (LCM) coupled real-time PCR indicated that elevated MMPs in diabetic skin were primarily expressed in the dermis. Furthermore, diabetic skin shows increased lysyl oxidase (LOX) expression and higher cross-linked collagens. Atomic force microscopy (AFM) further indicated that collagen fibrils were fragmented/disorganized, and key mechanical properties of traction force and tensile strength were increased in diabetic skin, compared to intact/well-organized collagen fibrils in non-diabetic skin. In in vitro tissue culture system, multiple MMPs including MMP-1 and MM-2 were induced by high glucose (25 mM) exposure to isolated primary human skin dermal fibroblasts, the major cells responsible for collagen homeostasis in skin. The elevation of MMPs and LOX over the years is thought to result in the accumulation of fragmented and cross-linked collagen, and thus impairs dermal collagen structural integrity and mechanical properties in diabetes. Our data partially explain why old-looking skin is more common in diabetic patients.