Abnormal Fibroblast Research Articles

Abnormal Fibroblasts Drive Pigmentary Skin Lesions in a Mouse Model of Carney Complex

Carney complex (CNC) is a rare autosomal dominant tumor predisposition syndrome that features focal skin pigmentation, myxomas, endocrine overactivity, and pigmented schwannomas (Carney et al., 1985). Abnormal skin pigmentation is seen in >80% of patients with the syndrome. Although lentiginosis in the central face, lips, and other areas (e.g., inside the mouth, canthus of the eyes, external genitalia) is the most common finding (Figure 1), individuals may also have Spitz, blue, or other nevi (Saggini and Brandi, 2011).

Porous Se@SiO2 Nanoparticles Enhance Wound Healing by ROS-PI3K/Akt Pathway in Dermal Fibroblasts and Reduce Scar Formation

Hypertrophic scarring, which is characterized by excessive extracellular matrix deposition and abnormal fibroblast homeostasis, is an undesirable outcome of dermal wound healing. Once formed, the scar will replace the normal function of local skin, and there are few noninvasive clinical treatments that can cure it. Se@SiO2 nanoparticles were synthesized to suppress oxidative stress, which induced the presence and activation of myofibroblasts during wound recovery. The characterization, antioxidant capacity and biological safety of Se@SiO2 NPs were evaluated. A full-thickness excisional wound model was established, and the wounds were divided into three groups. The re-epithelization and distribution of collagen fibers were assessed using hematoxylin and eosin staining and Masson’s trichome staining after specific treatments. Our results revealed that the Se@SiO2 NPs accelerated dermal wound healing and suppressed the formation of hypertrophic scars, accompanied by oxidative stress inhibition. Moreover, we found that Se@SiO2 NPs worked by activating the PI3K/Akt pathway and upregulating the phosphorylation of Akt. The findings of our study provide a new method to promote dermal scar-free wound healing by suppressing excessive oxidative stress and through PI3K/Akt pathway activation.

Dihydromyricetin Alleviates Pulmonary Fibrosis by Regulating Abnormal Fibroblasts Through the STAT3/p-STAT3/GLUT1 Signaling Pathway.

Background: Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive disorder with a poor prognosis. Although dihydromyricetin (DHM), extracted from vine tea and other Ampelopsis species, has been proven to have anti-inflammatory and antioxidant functions, the effects of DHM on IPF remain unclear. Methods: The effects of DHM on the differentiation, migration, proliferation, and respiratory functions of primary mouse lung fibroblasts (PMLFs) and primary human lung fibroblasts (PHLFs) were detected by western blotting, the Transwell assay, EdU staining, and the Mito Stress test. Then, the impacts of DHM on bleomycin (BLM)-induced pulmonary fibrosis were evaluated by pathological staining, western blotting, and coimmunofluorescence staining. The signaling pathway influenced by DHM was also investigated. Results: DHM could regulate the differentiation of fibroblasts to myofibroblasts and suppress the abnormal migration, proliferation, and respiratory functions of myofibroblasts induced by TGF-β1 or myofibroblasts from IPF patients. DHM could also alleviate pulmonary fibrosis induced by BLM. All these effects were achieved by regulating the STAT3/p-STAT3/GLUT1 signaling pathway. Conclusion: DHM could regulate the abnormal functions of myofibroblasts induced by TGF-β1 and myofibroblasts from IPF patients and alleviate pulmonary fibrosis induced by BLM; thus, DHM might be a candidate medicinal treatment for IPF.

Multi-omics approach characterises CRLS1 deficiency, a novel mitochondrial disorder

Introduction: The increasing integration of high-throughput genomic strategies, particularly whole exome (WES) and genome sequencing (WGS) has revolutionised mitochondrial diagnostics with the discovery of a growing list of novel disease genes. Application of ‘multi-omics’ technologies including proteomics, lipidomics and transcriptomics will improve the diagnostic gap. Case report: We present two individuals with progressive encephalopathy and biallelic variants identified on WES in the cardiolipin synthase 1 (CRLS1) gene. Additionally, the female infant had hypertrophic cardiomyopathy, bull’s eye maculopathy, auditory neuropathy, diabetes insipidus and died at 3.5 months. The 19-year-old male presented with neurodevelopmental regression, congenital nystagmus, sensorineural hearing loss and acquired microcephaly. Results: Respiratory chain enzyme analysis of skeletal muscle showed low Complex IV activity in the first patient. Mitochondrial morphology and biogenesis were impaired in her fibroblasts. Expression of wild-type CRLS1 restored her abnormal fibroblast morphology. Fibroblast proteomic profiling and mouse Crls1 knockout cell lines identified endoplasmic reticular, mitochondrial stress responses, and varying degrees of cardiolipin insufficiency. Lipid profiling in both demonstrated reduced cardiolipin levels, altered acyl-chain composition and significantly increased levels of phosphatidylglycerol. Collectively, these findings support that deleterious CRLS1 variants cause a novel mitochondrial disorder with multisystemic involvement. Conclusion: Innovative multi-omics approaches help establish novel diagnoses and provide insights into disease mechanisms.

Dual inhibition of \u03b1v\u03b26 and \u03b1v\u03b21 reduces fibrogenesis in lung tissue explants from patients with IPF

Rationaleαv integrins, key regulators of transforming growth factor-β activation and fibrogenesis in in vivo models of pulmonary fibrosis, are expressed on abnormal epithelial cells (αvβ6) and fibroblasts (αvβ1) in fibrotic lungs.ObjectivesWe evaluated multiple αv integrin inhibition strategies to assess which most effectively reduced fibrogenesis in explanted lung tissue from patients with idiopathic pulmonary fibrosis.MethodsSelective αvβ6 and αvβ1, dual αvβ6/αvβ1, and multi-αv integrin inhibitors were characterized for potency, selectivity, and functional activity by ligand binding, cell adhesion, and transforming growth factor-β cell activation assays. Precision-cut lung slices generated from lung explants from patients with idiopathic pulmonary fibrosis or bleomycin-challenged mouse lungs were treated with integrin inhibitors or standard-of-care drugs (nintedanib or pirfenidone) and analyzed for changes in fibrotic gene expression or TGF-β signaling. Bleomycin-challenged mice treated with dual αvβ6/αvβ1 integrin inhibitor, PLN-74809, were assessed for changes in pulmonary collagen deposition and Smad3 phosphorylation.Measurements and main resultsInhibition of integrins αvβ6 and αvβ1 was additive in reducing type I collagen gene expression in explanted lung tissue slices from patients with idiopathic pulmonary fibrosis. These data were replicated in fibrotic mouse lung tissue, with no added benefit observed from inhibition of additional αv integrins. Antifibrotic efficacy of dual αvβ6/αvβ1 integrin inhibitor PLN-74809 was confirmed in vivo, where dose-dependent inhibition of pulmonary Smad3 phosphorylation and collagen deposition was observed. PLN-74809 also, more potently, reduced collagen gene expression in fibrotic human and mouse lung slices than clinically relevant concentrations of nintedanib or pirfenidone.ConclusionsIn the fibrotic lung, dual inhibition of integrins αvβ6 and αvβ1 offers the optimal approach for blocking fibrogenesis resulting from integrin-mediated activation of transforming growth factor-β.

Who am I? (re-)Defining fibroblast identity and immunological function in the age of bioinformatics.

Who am I? (re-)Defining fibroblast identity and immunological function in the age of bioinformatics.

Identification of Potential Pathogenic Super-Enhancers-Driven Genes in Pulmonary Fibrosis.

Abnormal fibroblast differentiation into myofibroblast is a crucial pathological mechanism of pulmonary fibrosis (PF). Super-enhancers, a newly discovered cluster of regulatory elements, are regarded as the regulators of cell identity. We speculate that abnormal activation of super-enhancers must be involved in the pathological process of PF. This study aims to identify potential pathogenic super-enhancer-driven genes in PF. Differentially expressed genes (DEGs) in PF mouse lungs were identified from a GEO dataset (GDS1492). We collected super-enhancers and their associated genes in human lung fibroblasts and mouse embryonic fibroblasts from SEA version 3.0, a network database that provides comprehensive information on super-enhancers. We crosslinked upregulated DEGs and super-enhancer-associated genes in fibroblasts to predict potential super-enhancer-driven pathogenic genes in PF. A total of 25 genes formed an overlap, and the protein-protein interaction network of these genes was constructed by the STRING database. An interaction network of transcription factors (TFs), super-enhancers, and associated genes was constructed using the Cytoscape software. Gene enrichment analyses, including KEGG pathway and GO analysis, were performed for these genes. Latent transforming growth factor beta (TGF-β) binding protein 2 (LTBP2), one of the predicted super-enhancer-driven pathogenic genes, was used to verify the predicted network’s accuracy. LTBP2 was upregulated in the lungs of the bleomycin-induced PF mouse model and TGF-β1-stimulated mouse and human fibroblasts. Myc is one of the TFs binding to the LTBP2 super-enhancer. Knockout of super-enhancer sequences with a CRISPR/Cas9 plasmid or inhibition of Myc all decreased TGF-β1-induced LTBP2 expression in NIH/3 T3 cells. Identifying and interfering super-enhancers might be a new way to explore possible therapeutic methods for PF.

Bilayer dissolving microneedle array containing 5-fluorouracil and triamcinolone with biphasic release profile for hypertrophic scar therapy

Hypertrophic scar (HS) is an undesirable skin abnormality following deep burns or operations. Although intralesional multi-injection with the suspension of triamcinolone acetonide (TA) and 5-fluorouracil (5-Fu) has exhibited great promise to HS treatment in clinical, the difference of metabolic behavior between TA and 5-Fu remarkably compromised the treatment efficacy. Besides, the traditional injection with great pain is highly dependent on the skill of the experts, which results in poor compliance. Herein, a bilayer dissolving microneedle (BMN) containing TA and 5-Fu (TA-5-Fu-BMN) with biphasic release profile was designed for HS therapy. Equipped with several micro-scale needle tips, the BMN could be self-pressed into the HS with uniform drug distribution and less pain. Both in vitro permeation and in vivo HS retention tests revealed that TA and 5-Fu could coexist in the scar tissue for a sufficient time period due to the well-designed biphasic release property. Subsequently, the rabbit ear HS model was established to assess therapeutic efficacy. The histological analysis showed that TA-5-Fu-BMN could significantly reduce abnormal fibroblast proliferation and collagen fiber deposition. It was also found that the value of scar elevation index was ameliorated to a basal level, together with the downregulation of mRNA and protein expression of Collagen I (Col I) and transforming growth factor-β1 (TGF-β1) after application of TA-5-Fu-BMN. In conclusion, the BMN with biphasic release profiles could serve as a potential strategy for HS treatment providing both convenient administrations as well as controlled drug release behavior.

Exoantigens of Paracoccidioides spp. Promote Proliferation and Modulation of Human and Mouse Pulmonary Fibroblasts.

Paracoccidioidomycosis (PCM) is a systemic granulomatous fungal infection caused by thermally dimorphic fungi of the genus Paracoccidioides. Endemic in Latin America, PCM presents with high incidence in Brazil, Colombia, and Venezuela, especially among rural workers. The main clinical types are acute/subacute (AF) form and chronic form (CF). Even after effective antifungal treatment, patients with CF usually present sequelae, such as pulmonary fibrosis. In general, pulmonary fibrosis is associated with dysregulation wound healing and abnormal fibroblast activation. Although fibrogenesis is recognized as an early process in PCM, its mechanisms remain unknown. In the current study, we addressed the role of Paracoccidioides spp. exoantigens in pulmonary fibroblast proliferation and responsiveness. Human pulmonary fibroblasts (MRC-5) and pulmonary fibroblasts isolated from BALB/c mice were cultivated with 2.5, 5, 10, 100, and 250 µg/ml of exoantigens produced from P. brasiliensis (Pb18 and Pb326) and P. lutzii (Pb01, Pb8334, and Pb66) isolates. Purified gp43, the immunodominant protein of P. brasiliensis exoantigens, was also evaluated at concentrations of 5 and 10 µg/ml. After 24 h, proliferation and production of cytokines and growth factors by pulmonary fibroblasts were evaluated. Each exoantigen concentration promoted a different level of interference of the pulmonary fibroblasts. In general, exoantigens induced significant proliferation of both murine and human pulmonary fibroblasts (p < 0.05). All concentrations of exoantigens promoted decreased levels of IL-6 (p < 0.05) and VEGF (p < 0.05) in murine fibroblasts. Interestingly, decreased levels of bFGF (p < 0.05) and increased levels of TGF-β1 (p < 0.05) and pro-collagen I (p < 0.05) were observed in human fibroblasts. The gp43 protein induced increased TGF-β1 production by human cells (p = 0.02). In conclusion, our findings showed for the first time that components of P. brasiliensis and P. lutzii interfered in fibrogenesis by directly acting on the biology of pulmonary fibroblasts.

Serum Fibroblast Growth Factor 19 As A Predictor and Follow Up of Hepatocellular Carcinoma

Background: Abnormal autocrine fibroblast growth factor 19 (FGF19) productions have been observed in several types of cancers, including hepatocellular carcinoma (HCC), which is considered 3rd cause of cancer deaths worldwide with gradually increased incidence. Objective: To investigate the role of FGF 19 in prediction, diagnosis and follow up of HCC together with alpha feto protein (αFP). Patients and methods: This study was carried in Internal Medicine Department and Clinical Pathology Department, Faculty of Medicine Zagazig University Egypt in the period from October 2017 to October 2020. The study included 150 patients (111 males and 39 females) classified into 3 groups: 50 healthy volunteers as a control, 50 patients with liver cirrhosis documented by examination and investigation and 50 Patients with HCC with variable sizes. All participants in the study were subjected for the following after written consent and approval by their search ethics committee of Zagazig University. Result: The median of FGF19 level between control, liver cirrhosis and HCC was 4, 6 and 10 87 pg/ml respectively with higher sensitivity for detection of small HCC with high significance of α Fp between HCC > cirrhosis > control. Conclusion: FGF19 can be used successfully as a novel biomarker for HCC diagnosis and follow up after treatment together with already existing biomarker α FP.

Pien Tze Huang accelerated wound healing by inhibition of abnormal fibroblast apoptosis in Streptozotocin induced diabetic mice

Ethnopharmacological relevanceDiabetic foot ulcer is one of the most serious complications of diabetes. Effective medical treatment regarding improvement of ulcer healing in patients is essential. Pien Tze Huang (PZH), a valuable Chinese traditional medicine, has been found significant efficacy on the curing of diabetic wound in clinic recently. Aim of the studyThis work was conducted to confirm the efficacy, and compare the therapeutic effect through the oral administration and local delivery route, providing a rationale for the new PZH form development; besides, the mechanisms through which PZH promoted the wound healing was also discussed. Materials and methodsFirst, the chemical composition of PZH was characterized by 1H-NMR and HPLC. The anti-apoptosis effects of PZH on high concentration glucose injured epidermal fibroblast (HFF-1) was investigated in a dose dependent way. Then, the effects of the systematical administration of PZH, and the topical used route on excisional wounds of Streptozotocin (STZ) induced diabetic mice were compared. ResultsThe results illustrated that PZH decreased the reactive oxygen species (ROS) levels in cells, preventing cell damage/apoptosis through an ROS/Bcl-2/Bax/Caspase-3 pathway. The in vivo study proved that topical use of PZH exceeded the systematical route both in accelerating the wound closure and improving the healing quality. Meanwhile, PZH promoted wound closure through stimulating the secretion of Col-I, decreasing fibroblast apoptosis, and enhancing myo-fibroblast differentiation, in consistent with the mechanism study in vitro. ConclusionsLocal used PZH improves wound healing by inhibiting the abnormal HFF-1 apoptosis and senescence. The study held a great promise for development of a topical dosage form of PZH for diabetic wound healing.

MicroRNA-122 aggravates angiotensin II-mediated apoptosis and autophagy imbalance in rat aortic adventitial fibroblasts via the modulation of SIRT6-elabela-ACE2 signaling

Abnormal aortic adventitial fibroblasts (AFs) play essential roles in the development of vascular remodeling and disorders. Previous studies revealed that microRNA-122 (miR-122) levels were elevated in the aortic adventitia of hypertensive rats with vascular injury. Here, we aim to evaluate the biological effects and underlying mechanisms of miR-122 in rat AFs. Exposure to angiotensin II (ATII) in rat AFs resulted in decreased levels of sirtuin 6 (SIRT6), elabela (ELA), and angiotensin-converting enzyme 2 (ACE2). Additionally, stimulation with ATII contributed to a decline in autophagic flux and obvious increases in cellular migration, oxidative stress, and apoptosis, which were exacerbated by the transfection of miR-122-5p mimic but were rescued by miR-122-5p inhibitor, exogenous replenishment of ELA, and recombinant adeno-associated virus expressing SIRT6 (rAAV-SIRT6), respectively. Moreover, stimulation with miR-122-5p mimic led to a marked reduction in the levels of SIRT6 and ELA in rat AFs, which were elevated by stimulation with rAAV-SIRT6. Furthermore, miR-122-5p inhibitor-mediated pro-autophagic, anti-oxidant and anti-apoptotic effects in rat AFs were partially suppressed by 3-methyladenine, SIRT6 small interfering RNA (siRNA) and ELA siRNA, which were linked with the downregulation in the protein levels of LC3-II, beclin-1, and ACE2 and the upregulation of p62 expression and bax/bcl-2 ratio. Our findings indicated that miR-122-5p inhibition prevented ATII-mediated loss of autophagy, and the promotion of apoptosis and oxidative stress via activating the SIRT6-ELA-ACE2 signaling. MiR-122-5p may be a novel predictive biomarker of adventitial injury, and targeting the SIRT6-ELA-ACE2 signaling may have the potential therapeutic importance of controlling vascular remodeling and disorders.

Notch3 Modulates Cardiac Fibroblast Proliferation, Apoptosis, and Fibroblast to Myofibroblast Transition via Negative Regulation of the RhoA/ROCK/Hif1α Axis.

Cardiac fibrosis is a common pathological process in multiple cardiovascular diseases, including myocardial infarction (MI). Abnormal cardiac fibroblast (CF) activity is a key event in cardiac fibrosis. Although the Notch signaling pathway has been reported to play a vital role in protection from cardiac fibrosis, the exact mechanisms underlying cardiac fibrosis and protection from it have not yet been elucidated. Similarly, Hif1α and the RhoA/ROCK signaling pathway have been shown to participate in cardiac fibrosis. The RhoA/ROCK signaling pathway has been reported to be an upstream pathway of Hif1α in several pathophysiological processes. In the present study, we aimed to determine the effects of notch3 on CF activity and its relationship with the RhoA/ROCK/Hif1α signaling pathway. Using in vitro experiments, we demonstrated that notch3 inhibited CF proliferation and fibroblast to myofibroblast transition (FMT) and promoted CF apoptosis. A knockdown of notch3 using siRNAs had the exact opposite effect. Next, we found that notch3 regulated CF activity by negative regulation of the RhoA/ROCK/Hif1α signaling pathway. Extending CF-based studies to an in vivo rat MI model, we showed that overexpression of notch3 by the Ad-N3ICD injection attenuated the increase of RhoA, ROCK1, ROCK2, and Hif1α levels following MI and further prevented MI-induced cardiac fibrosis. On the basis of these results, we conclude that notch3 is involved in the regulation of several aspects of CF activity, including proliferation, FMT, and apoptosis, by inhibiting the RhoA/ROCK/Hif1α signaling pathway. These findings are significant to further our understanding of the pathogenesis of cardiac fibrosis and to ultimately identify new therapeutic targets for cardiac fibrosis, potentially based on the RhoA/ROCK/Hif1α signaling pathway.

Chondroitin Sulfate Promotes the Proliferation of Keloid Fibroblasts Through Activation of the Integrin and Protein Kinase B Pathways.

Keloids are dermal fibroproliferative tumors that arise beyond the boundary of the original wound edges and invades adjacent tissue. Keloids are characterized by the extensive production of extracellular matrix (ECM) and abnormal fibroblast proliferation. Chondroitin sulfate (CS) is one of the major structural components of cartilage and ECM. Recently, we reported the over-accumulation of CS in keloid lesions. Keloid-derived fibroblasts (KFs) and normal dermal fibroblasts (NFs) were incubated with CS. The fibroblast proliferation rate was analyzed using a tetrazolium salt colorimetric assay. The activation of the intracellular signaling pathway was analyzed by Western blotting. Wortmannin, a PI3K inhibitor, and anti-integrin antibodies were tested to investigate the mechanism of the CS-induced cell proliferation. CS strongly stimulated the proliferation of KFs, but not NFs. The analysis of the intracellular signal transduction pathway revealed that the stimulation effect of CS on KF proliferation was due to the activation of the protein kinase B (AKT) pathway and that integrin α1 was responsible for this phenomenon. We revealed that CS probably activates the AKT pathway through integrin to induce KF proliferation. CS may be a novel clinical therapeutic target in keloids.

Epidemiology and pathogenesis of heart failure with preserved ejection fraction.

Heart failure (HF) is a complex syndrome that affects approximately6.5 millionadults in the United States. About half of the 6.5 million adults with HF are estimated to be individuals with heart failure with preserved ejection fraction (HFpEF). It is a common cause for poor quality of life, increased health-care resource utilization, and early mortality. HF incidence has risen to epidemic proportions in the recent years. This review attempts to address the epidemiology and pathophysiology of HFpEF. The incidence of HFpEF increased from 48% to 57% from 2000 to 2007 with a slight decrease in 2010 to 52%. The temporal trends in heart failure show an overall stable incidence of HF over the last two decades with increasing incidence of HFpEF and decreasing HFrEF incidence. Many etiologies contribute to the development of HFpEF which makes the treatment very challenging. Pathophysiology of HFpEF is multifaceted stemming from several disease-specific aspects of inflammation and endothelial function, cardiomyocyte hypertrophy and fibrosis, ventricular-vascular uncoupling, pulmonary hypertension and chronotropic incompetence. Hence identifying the risk factors and etiologies is imperative to achieve optimal outcomes in this population. Newer insights into myocardial remodeling have led to an interesting finding of abnormal fibroblasts in HFpEF which are apoptosis resistant and initiate the development of an abnormal myocardial matrix resulting in initiation and progression of the disease. Upregulation of ROS has also been implicated in HFpEF. Further investigation could provide new avenues to target therapeutics specifically to stop initiation and progression of fibrosis.

Heart failure as interstitial cancer: emergence of a malignant fibroblast phenotype.

A prolonged state of left ventricular pressure overload, commonly caused by hypertension and aortic valve disease, promotes remodelling of the myocardium that can progress to heart failure with preserved ejection fraction (HFpEF). In animal models, a major factor driving progression from pressure-overload hypertrophy (POH) to HFpEF is the activation and proliferation of an abnormal fibroblast phenotype that is resistant to apoptosis, degrades normal stromal matrix and is replaced with a fibrotic matrix structure. A similar fibroblast phenotype has been identified in the stroma of solid cancers. This cancer-associated fibroblast drives tumour growth and invasion. The proliferation and expansion of these abnormal fibroblast populations in both HFpEF and cancer contribute to progression of disease. In early-phase clinical trials, chemotherapeutic agents targeting cancer-associated fibroblasts had antitumour properties. In this Perspectives article, we postulate that, because the abnormal fibroblast populations in POH and cancer have identical characteristics, chemotherapeutic agents targeting the POH-related fibroblast might attenuate the development of myocardial fibrosis, a pathophysiological hallmark of HFpEF. These agents must be designed to target the abnormal fibroblasts with high specificity because many classes of chemotherapeutic drugs can themselves cause myocardial dysfunction and heart failure.

657 Induction of IL-11 expression leads to persistent abnormal fibroblast activity in cutaneous wound healing

Injury of the skin can provoke excessive accumulation of extracellular matrix (ECM) leading to a hypertrophic scar or keloid development. However, the mechanism responsible for the persistence of the fibrotic response in a wound healing process is yet not well understood. There is growing evidence that abnormal fibroblast activity mediated by IL-11 signalling plays the pivotal role in systemic organ fibrosis. Therefore, we investigated whether the pathologic activity of myofibroblast-like keloid fibroblast (KFs) are potentiated by hypoxia-induced mesenchymal transition mediated by IL-11. Keloid tissue derived from patients’ samples exhibited increased expression IL-11 mRNA compared with adjacent normal skin. The expression of functional IL-11R mRNA was variable depending on the sample site; adjacent normal skin, margin, and center. KFs cultured in hypoxic conditions (1% O2) and the expression of hypoxia-inducible factor-1α (HIF-1α) and mesenchymal transition markers (E-cadherin, vimentin, α-SMA, and type I collagen) were increased. IL-11 mRNA expression was induced in KFs by hypoxia while silencing IL-11 suppressed the induction of fibrosis markers (α-SMA and type I collagen). Taken together, these results suggest that IL-11 is a mediator in hypoxia-induced abnormal fibroblast activation in scar fibrosis.

Hypoxia-Induced Epithelial-To-Mesenchymal Transition Mediates Fibroblast Abnormalities via ERK Activation in Cutaneous Wound Healing.

Previous studies described the involvement of extracellular signal-related kinase (ERK) in systemic fibrotic diseases, but the role of ERK in cutaneous scarring is unknown. Although hypoxia drives tissue fibrosis by activating hypoxia-inducible factor-1α (HIF-1α), the specific roles of hypoxia and associated ERK phosphorylation in abnormal fibroblast activity during cutaneous scarring are unclear. Here, we investigated whether pathologic myofibroblast-like keloid fibroblast activity is promoted by hypoxia-induced epithelial–mesenchymal transition mediated by ERK activation. ERK phosphorylation was significantly increased in keloid tissue and fibroblasts. Human dermal fibroblasts cultured under hypoxia (1% O2) expressed phosphorylated ERK and exhibited activation of p38 mitogen-activated protein kinase signaling. Hypoxic human dermal fibroblasts showed increased protein and mRNA levels of epithelial–mesenchymal transition markers. Furthermore, administration of an ERK inhibitor (SCH772984) reduced the hypoxia-induced elevation of collagen type I levels in human dermal fibroblasts. Therefore, ERK may be a promising therapeutic target in profibrogenic diseases.

937 Induction of IL-11 expression leads to persistent abnormal fibroblast activity in cutaneous wound healing

937 Induction of IL-11 expression leads to persistent abnormal fibroblast activity in cutaneous wound healing

Immunohistochemical examination in arthrofibrosis of the knee joint.

Arthrofibrosis (AF) is the result of increased cell proliferation and synthesis of matrix proteins (collagen I, III, and VI). Especially after invasive knee surgery, e.g., ligament reconstruction or knee replacement, abnormal fibroblast proliferation with pathological periarticular fibrosis can be observed leading to severely limited joint motion. The pathogenesis of AF is currently not fully understood. The present work aims to determine pathogenic factors. A descriptive, histological and immunohistochemical comparative study was performed on tissue samples of 14 consecutive patients undergoing arthrolysis for joint stiffness due to AF. Seven human autopsy specimens served as control. Samples were stained for expression of relevant markers such as CD68, α-smooth muscle actin (ASMA), beta-catenin, BMP-2 and examined for the histological grade of AF (cell-rich versus cell-poor) and compared to a control. Furthermore, a microscopic evaluation of the samples for cell differentiation and number was performed. Tissue sections of cell-rich fibrosis showed a significantly higher expression of CD68 compared to the control with less than 10% of CD68 positive cells (p = 0.002). In cell-poor fibrosis no statistically significant difference was obvious (p = 0.228). Expression of ASMA in synovia, vessels, cell-rich and cell-poor fibrosis showed median values of 2.00 in the AF group and 1.75 in the control. Both groups differed significantly (p = 0.003). AF tissue showed a significantly difference in expression of β-catenin (p < 0.001) compared to the control. The overall difference between AF and control group in expression of BMP-2 was also statistically significant (p = 0.002). Expression of CD68, ASMA, beta-catenin and BMP-2 is significantly increased in AF tissue samples. Based on presented findings, histological evaluation and immunohistochemical assessment of CD68, ASMA, β-catenin and BMP-2 expression may proof useful to diagnose AF and to analyze AF activity.