Loss of Jagged1 in mature endothelial cells causes vascular dysfunction with alterations in smooth muscle phenotypes.

BACKGROUND: Notch signaling is an evolutionarily conserved pathway that functions via direct cell-cell contact. The Notch ligand Jagged1 (Jag1) has been extensively studied in vascular development, particularly for its role in smooth muscle cell maturation. Endothelial cell-expressed Jag1 is essential for blood vessel formation by signaling to nascent vascular smooth muscle cells and promoting their differentiation. Given the established importance of Jag1 in endothelial cell/smooth muscle crosstalk during development, we sought to determine the extent of this communication in the adult vasculature for blood vessel function and homeostasis. METHODS: We conditionally deleted Jag1 in endothelial cells of adult mice and examined the phenotypic consequences on smooth muscle cells of the vasculature. RESULTS: Our results show that genetic loss of Jag1 in endothelial cells has a significant impact on Notch signaling and vascular smooth muscle function in mature blood vessels. Endothelial cell-specific deletion of Jag1 causes a concomitant loss of JAG1 and NOTCH3 expression in vascular smooth muscle cells, resulting in a transition to a less differentiated state. Aortic vascular smooth muscle cells isolated from the endothelial cell-specific Jag1 deficient mice retain an altered phenotype in culture with fixed changes in gene expression and reduced Notch signaling. Utilizing comparative RNA-sequence analysis, we found that Jag1 deficiency preferentially affects extracellular matrix and adhesion protein gene expression. Vasoreactivity studies revealed a reduced contractile response and impaired agonist-induced relaxation in endothelial cell Jag1-deficient aortas compared to controls. CONCLUSIONS: These data are the first to demonstrate that Jag1 in adult endothelial cells is required for the regulation and homeostasis of smooth muscle cell function in arterial vessels partially through the autoregulation of Notch signaling and cell matrix/adhesion components in smooth muscle cells.

The Notch Pathway: A Link Between COVID-19 Pathophysiology and Its Cardiovascular Complications.

COVID-19 is associated with a large number of cardiovascular sequelae, including dysrhythmias, myocardial injury, myocarditis and thrombosis. The Notch pathway is one likely culprit leading to these complications due to its direct role in viral entry, inflammation and coagulation processes, all shown to be key parts of COVID-19 pathogenesis. This review highlights links between the pathophysiology of SARS-CoV2 and the Notch signaling pathway that serve as primary drivers of the cardiovascular complications seen in COVID-19 patients.

Icariin protects against thioacetamide-induced liver fibrosis in rats: Implication of anti-angiogenic and anti-autophagic properties.

BACKGROUND: Liver fibrosis is a major health problem. The current study evaluated the potential of icariin (ICA) to guard against thioacetamide (TAA)-induced liver fibrosis in rats. METHODS: Four groups of male rats were treated as follows: group 1 was the control group, group 2 was given TAA (200mg/kg), group 3 was administered ICA (50mg/kg) and TAA (200mg/kg), and group 4 was given ICA (50mg/kg) alone. Animal treatment was continued for four weeks. RESULTS: Co-administration of ICA guarded against TAA hepatotoxicity as indicated by significant inhibition in the rise of serum ALT and AST activities and albumin concentrations. This was accompanied by inhibition of reduced glutathione depletion, superoxide dismutase exhaustion, and lipid peroxide accumulation. In addition, ICA inhibited the pathological alterations in liver architecture induced by TAA. The antifibrotic activity of ICA was verified by reduced hepatic collagen deposition in liver sections stained with Masson's trichrome and hepatic Col-1α mRNA and hydroxyproline contents compared to the TAA-treated group. The antiangiogenic activity of ICA was evidenced by lowered levels of mRNA of Ang-1 and protein expression of VEGF, PDGF-ß, and CTGF immunohistochemically. Further, the anti-autophagic property of ICA was evidenced by amelioration of the decrease in mTOR and p70S6 kinase expression and an increase in TLR4, NFκB, IL1-ß, and COX-2 immunohistochemically. Moreover, ICA antagonized the increase in HMGB1, TGF-ß, and Beclin-1 and the decrease in BAMBI hepatic mRNA levels. CONCLUSIONS: ICA inhibits TAA-induced liver fibrosis in rats, possibly via inhibition of angiogenesis and autophagy.

Influence of Onabotulinumtoxin A on testes of the growing rat.

Onabotulinumtoxin A (onabotA) is gaining wide medical use in children. The present study was planned to investigate the influence of its injection on the maturing testicular structures in rats. Immature rats were injected in the bilateral cremaster muscles by onabotA with three doses of (10, 20, and 40 U/kg) three times in a 2-week interval. The effect of these injections on fertility indices was examined. Levels of antisperm antibodies and several apoptosis parameters were also investigated. DNA content in form of ploidy and histopathological alterations were assessed. OnabotA-injected groups showed decreased sperm count and semen quality, while sperm vitality, morphology, and testosterone levels were not significantly affected. Furthermore, DNA flow cytometric analysis confirmed delayed sperm maturation. Apoptosis markers were significantly increased by the injections. In conclusion, onabotA injection in growing rats adversely affected sperm count and maturation. OnabotA testicular effects are mediated, at least partly, by apoptosis.

Adverse testicular effects of Botox® in mature rats.

Botox® injections are taking a consistently increasing place in urology. Intracremasteric injections, particularly, have been applied for cryptorchidism and painful testicular spasms. Studies outlining their safety for this use are, however, scanty. Thus, the present study aimed at evaluating possible testicular toxicity of Botox® injections and their effect on male fertility. Mature rats were given intracremasteric Botox® injections (10, 20 and 40 U/kg) three times in a two-week interval. Changes in body and testes weights were examined and gonadosomatic index compared to control group. Semen quality, sperm parameters, fructose, protein, cholesterol and triglycerides contents were assessed. Effects on normal testicular function were investigated by measuring testosterone levels and changes in enzyme activities (lactate dehydrogenase-X and acid phosphatase). To draw a complete picture, changes in oxidative and inflammatory states were examined, in addition to the extent of connective tissue deposition between seminiferous tubules. In an attempt to have more accurate information about possible spermatotoxic effects of Botox®, flowcytometric analysis and histopathological examination were carried out. Botox®-injected rats showed altered testicular physiology and function. Seminiferous tubules were separated by dense fibers, especially with the highest dose. Flowcytometric analysis showed a decrease in mature sperms and histopathology confirmed the findings. The oxidative state was, however, comparable to control group. This study is the first to show that intracremasteric injections of Botox® induce adverse testicular effects evidenced by inhibited spermatogenesis and initiation of histopathological changes. In conclusion, decreased fertility may be a serious problem Botox® injections could cause.

Multimechanistic antifibrotic effect of biochanin a in rats: implications of proinflammatory and profibrogenic mediators.

OBJECTIVE: Biochanin A (BCA) is an isoflavone found in red clover and peanuts. Recently, it drew much attention as a promising anticancer and antioxidant. Due to its diversity in pharmacological actions, we were encouraged to investigate its potential as an antifibrotic, elucidating the different molecular mechanisms involved. DESIGN: Rats were pretreated with BCA, then injected with carbon tetrachloride (CCl4) for 6 weeks. Changes in liver weight and histology were examined and levels of aspartate and alanine aminotransferases, cholesterol, triglycerides, alkaline phosphatase and total bilirubin measured. To assess hepatic efficiency, indocyanine green was injected and its clearance calculated and albumin, total proteins and insulin-like growth factor-1 expression were measured. Cytochrome P4502E1 activity, cytochrome P4501A1 expression, in addition to sulfotransferase1A1 expression were determined to deduce the effect of BCA on hepatic metabolism. As oxidative stress markers, lipid peroxides levels, reduced glutathione, superoxide dismutase and catalase activities, as well as the total antioxidant capacity, were assessed. Nitric oxide, inducible nitric oxide synthase and cyclooxygenase-2 were used as indicators of the inflammatory response. Signaling pathways involving tumor necrosis factor-alpha, nuclear factor-kappa B, transforming growth factor-beta1, matrix metalloproteinase-9 and alpha-smooth muscle actin were investigated accordingly. Extent of fibrosis was examined by Masson's stain and measuring hydroxyproline levels. RESULTS: BCA pretreatment significantly protected against the chronic damage of CCl4. Liver injury, oxidative stress, inflammation and fibrosis markers decreased, while hepatic efficiency improved. CONCLUSION: Our findings suggested that BCA administration protects against fibrotic complications, a property that can be contributed to the multimechanistic approach of the drug.

Biochanin A protects against acute carbon tetrachloride-induced hepatotoxicity in rats.

Biochanin A (BCA) is an isoflavone found in red clover possessing multiple pharmacological activities including antimicrobial, antioxidant, and anticancer ones. The present study aimed to assess its hepatoprotective potential at different doses in a carbon tetrachloride (CCl4)-induced hepatotoxicity model in rats. The effects on hepatic injury were explored by measuring serum levels of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase. Furthermore, the serum levels of glucose, urea, creatinine, total bilirubin, total proteins, triglycerides, and total cholesterol were determined. The metabolic capacity of the liver was assessed by measuring changes in cytochrome P450 2E1 activity. The underlying mechanisms were substantiated by measuring oxidative stress markers as catalase, superoxide dismutase, glutathione peroxidase, glutathione transferase, glutathione reductase, reduced glutathione, total antioxidant capacity, and lipid peroxidation, as well as inflammation markers such as nitric oxide, inducible nitric oxide synthase, cyclooxygenase2, tumor necrosis factor-α, and leukocyte-common antigen. The results were confirmed by histopathological examination, and the median lethal dose was determined to confirm the safety of the drug. BCA successively protected against CCl4-induced damage, normalizing many parameters to that of the control group. The study indicates that BCA possesses multimechanistic hepatoprotective activity that can be attributed to its antioxidant, anti-inflammatory, and immunomodulatory actions.