Elevated c-fos expression is correlated with phenotypic switching of human vascular smooth muscle cells derived from lower limb venous varicosities

Pathophysiology and Genetic Associations of Varicose Veins: A Narrative Review

Varicose veins (VVs) have a high prevalence worldwide and have become a major medical burden. Their pathophysiology involves a complex interplay of inflammation and tissue remodeling, and current treatment is limited by its impact on the pathophysiological mechanisms. In addition, despite clear environmental factors, family history is an important risk factor, suggesting a genetic component to the risk of developing VVs. Our understanding of the pathogenesis of these diseases has benefited greatly from the expansion of population genetic studies, from pioneering family studies to large genome-wide association studies; we now find multiple risk loci for each venous disease. This review considers the pathophysiology of VVs, highlighting the current state of genetic knowledge. We also propose future directions for research.

Nitration of cAMP-Response Element Binding Protein Participates in Myocardial Infarction-Induced Myocardial Fibrosis via Accelerating Transcription of Col1a2 and Cxcl12

Aims: Myocardial fibrosis after myocardial infarction (MI) leads to heart failure. Nitration of protein can alter its function. cAMP-response element binding protein (CREB) is a key transcription factor involved in fibrosis. However, little is known about the role of nitrated CREB in MI-induced myocardial fibrosis. Meanwhile, downstream genes of transcription factor CREB in myocardial fibrosis have not been identified. This study aims to verify the hypothesis that nitrated CREB promotes MI-induced myocardial fibrosis via regulating the transcription of Col1a2 and Cxcl12. Results: Our study showed that (1) the level of nitrative stress was elevated and nitrated CREB was higher in the myocardium after MI. Tyr182, 307, and 336 were the nitration sites of CREB; (2) with the administration of peroxynitrite (ONOO^-) scavengers, CREB phosphorylation, nuclear translocation, and binding activity to TORC2 (transducers of regulated CREB-2) were attenuated; (3) the expressions of extracellular matrix (ECM) proteins were upregulated and downregulated in accordance with the expression alteration of CREB both in vitro and in vivo; (4) CREB accelerated transcription of Col1a2 and Cxcl12 after MI directly. With the administration of ONOO^- scavengers, ECM protein expressions were attenuated; meanwhile, the messenger RNA (mRNA) levels of Col1a2 and Cxcl12 were alleviated as well. Innovation and Conclusion: Nitration of transcription factor CREB participates in MI-induced myocardial fibrosis through enhancing its phosphorylation, nuclear translocation, and binding activity to TORCs, among which CREB transcripts Col1a2 and Cxcl12 directly. These data indicated that nitrated CREB might be a potential therapeutic target against MI-induced myocardial fibrosis.

Verständnis, Prävention und Behandlung von venösen und lymphatischen Erkrankungen basieren auf der Arbeit von Grundlagenforschern

Zweck Die Rolle der Grundlagenforschung in allen Bereichen der Medizin war, ist und wird auch immer kritisch sein. Die Grundlagenforschung leistet einen Beitrag zu Wissen und Fortschritt. In der Phlebologie ist es nicht anders. Das Manuskript beschreibt die neuesten Errungenschaften der Grundlagenforschung zum Thema Phlebologie.

Methode Der vorliegende Beitrag beleuchtet Publikationen mit dem Thema Grundlagenforschung in der Phlebologie aufgrund einer PubMed-Suche. Die gefundenen Artikel sowie die verschiedenen Schritte, die für Grundlagenforschung angewendet werden, werden diskutiert. Die Relevanz dieser Arbeiten in Bezug auf die tägliche Arbeit in der Phlebologie wird beleuchtet, insbesondere in Bezug auf die Veränderungen der Venenklappen, der Venenwand und den darauffolgenden Störungen des Blutstroms.

Ergebnisse Veränderte Venenwände bei Varizen sind das Ergebnis eines Umbauprozesses aufgrund von Veränderungen der Venenwand auf Zellebene sowie im Interstitium. An diesem Prozess sind glatte Muskelzellen beteiligt. Ferner wurde eine Transformation vom kontraktilen zum sekretorischen Phänotyp beschrieben. In diesem Umbaustadium sind Matrix-Metalloproteinasen (MMP) aktiv beteiligt. Sie tragen zur beobachteten endgültigen Veränderung der Venenwand bei Varizen bei. Die Eigenschaften des Blutstroms und die Funktion der Venenklappen haben sich als zusammenhängendes System erwiesen.

Schlussfolgerungen Die wissenschaftliche Methode ist der Grundpfeiler der Grundlagenforschung. Varizen entstehen durch einen veränderten Blutstrom und einen Umbau der Venenwand.

Vascular smooth muscle cell c-Fos is critical for foam cell formation and atherosclerosis

BACKGROUND

Hyperlipidemia-induced vascular smooth muscle cell (VSMC)-derived foam cell formation is considered a crucial event in the development of atherosclerosis. Since c-Fos emerges as a key modulator of lipid metabolism, we investigated whether c-Fos plays a role in hyperlipidemia-induced VSMC-derived foam cell formation and atherosclerosis.

APPROACH AND RESULTS

c-Fos expression was observed in VSMCs in atherosclerotic plaques from patients and western diet-fed atherosclerosis-prone LDLR^-/- and ApoE^-/- mice by immunofluorescence staining. To ascertain c-Fos's function in atherosclerosis development, VSMC-specific c-Fos deficient mice in ApoE^-/- background were established. Western diet-fed c-Fos^VSMCKOApoE^-/- mice exhibited a significant reduction of atherosclerotic lesion formation as measured by hematoxylin and eosin staining, accompanied by decreased lipid deposition within aortic roots as determined by Oil red O staining. Primary rat VSMCs were isolated to examine the role of c-Fos in lipid uptake and foam cell formation. oxLDL stimulation resulted in VSMC-derived foam cell formation and elevated intracellular mitochondrial reactive oxygen species (mtROS), c-Fos and LOX-1 levels, whereas specific inhibition of mtROS, c-Fos or LOX-1 lessened lipid accumulation in oxLDL-stimulated VSMCs. Mechanistically, oxLDL acts through mtROS to enhance transcription activity of c-Fos to facilitate the expression of LOX-1, exerting a feedforward mechanism with oxLDL to increase lipid uptake and propel VSMC-derived foam cell formation and atherogenesis.

CONCLUSION

Our study demonstrates a fundamental role of mtROS/c-Fos/LOX-1 signaling pathway in promoting oxLDL uptake and VSMC-derived foam cell formation during atherosclerosis. c-Fos may represent a promising therapeutic target amenable to clinical translation in the future.

Neuregulin (NRG-1β) Is Pro-Myogenic and Anti-Cachectic in Respiratory Muscles of Post-Myocardial Infarcted Swine

Neuregulin-1β (NRG-1β) is a growth and differentiation factor with pleiotropic systemic effects. Because NRG-1β has therapeutic potential for heart failure and has known growth effects in skeletal muscle, we hypothesized that it might affect heart failure-associated cachexia, a severe co-morbidity characterized by a loss of muscle mass. We therefore assessed NRG-1β's effect on intercostal skeletal muscle gene expression in a swine model of heart failure using recombinant glial growth factor 2 (USAN-cimaglermin alfa), a version of NRG-1β that has been tested in humans with systolic heart failure. Animals received one of two intravenous doses (0.67 or 2 mg/kg) of NRG-1β bi-weekly for 4 weeks, beginning one week after infarct. Based on paired-end RNA sequencing, NRG-1β treatment altered the intercostal muscle gene expression of 581 transcripts, including genes required for myofiber growth, maintenance and survival, such as MYH3, MYHC, MYL6B, KY and HES1. Importantly, NRG-1β altered the directionality of at least 85 genes associated with cachexia, including myostatin, which negatively regulates myoblast differentiation by down-regulating MyoD expression. Consistent with this, MyoD was increased in NRG-1β-treated animals. In vitro experiments with myoblast cell lines confirmed that NRG-1β induces ERBB-dependent differentiation. These findings suggest a NRG-1β-mediated anti-atrophic, anti-cachexia effect that may provide additional benefits to this potential therapy in heart failure.

Elevated serum homocysteine levels are associated with the development of chronic venous ulcers

INTRODUCTION

Venous ulceration is a multifactorial disease, and whether hyperhomocysteinemia (HHcy) promotes deterioration from primary varicose veins to venous ulcers remains unproven.

METHODS

This study retrospectively analyzed clinical data from 717 patients to investigate the potential correlation between HHcy and primary varicose veins ulcer formation, including 611 patients without ulcers (control group) and 106 with ulcers (case group).

RESULTS

In this study, 46.2% (49/106) of patients in the case group and 17.5% (107/611, p < 0.001) in the control group suffered from HHcy. Multivariate logistic analysis revealed that HHcy was closely associated with the incidence of venous ulceration in patients with primary varicose veins (p < 0.001). Propensity score matching created 101 matched pairs of patients with and without ulcers, and the analysis pointed to a potential link between HHcy and ulcer formation in the context of primary varicose veins (p < 0.001). Additional experiments showed that HHcy could induce endothelial dysfunction and phenotypic switching of vascular smooth muscle cells.

CONCLUSION

Both clinical and experimental findings implicated HHcy as a key factor in the development of venous ulceration. Further research is needed to appraise the effectiveness of HHcy-lowering therapy in the prevention of venous ulcers in patients with varicose veins.

MicroRNA‑199a‑5p regulates FOXC2 to control human vascular smooth muscle cell phenotypic switch

Varicose veins are among the most common disorders of the vascular system; however, the pathogenesis of varicose veins remains unclear. The present study aimed to investigate the roles of microRNA (miR)‑199a‑5p in varicose veins and in the phenotypic transition of vascular smooth muscle cells (VSMCs). Bioinformatics analysis confirmed that miR‑199a‑5p had target sites on the forkhead box C2 (FOXC2) 3'‑untranslated region. Reverse transcription‑quantitative PCR (RT‑qPCR) and western blotting were used to detect the expression levels of miR‑199a‑5p and FOXC2 in varicose vein and normal great saphenous vein tissues. Cell Counting Kit‑8 and Transwell migration assays were performed to validate the effects of miR‑199a‑5p on VSMCs. Contractile markers, such as smooth muscle 22α, calponin, smooth muscle actin and myosin heavy chain 11 were used to detect phenotypic transition. RT‑qPCR revealed that miR‑199a‑5p was downregulated in varicose veins compared with expression in normal great saphenous veins, whereas FOXC2 was upregulated in varicose veins. In addition, biomarkers of the VSMC contractile phenotype were downregulated in varicose veins. Overexpression of miR‑199a‑5p by mimics suppressed VSMC proliferation and migration, whereas depletion of miR‑199a‑5p enhanced VSMC proliferation and migration. Notably, the effects caused by miR‑199a‑5p could be reversed by FOXC2 overexpression. Dual luciferase reporter analysis confirmed that FOXC2 was a target of miR‑199a‑5p. In conclusion, miR‑199a‑5p may be a novel regulator of phenotypic switching in VSMCs by targeting FOXC2 during varicose vein formation.