β‑estradiol alleviates hypertension‑ and concanavalin A‑mediated inflammatory responses via modulation of connexins in peripheral blood lymphocytes

Estrogen Protects against Renal Ischemia-Reperfusion Injury by Regulating Th17/Treg Cell Immune Balance

Inflammation is a critical mediator of renal ischemia-reperfusion (I/R) injury (IRI), and T lymphocytes exert a key role in the renal IRI-induced inflammation. Connexin 43 (Cx43) is related to the maintenance of T lymphocyte homeostasis. Various preclinical researches have reported that estrogen is a renoprotective agent based on its anti-inflammatory potential. The present research is aimed at studying the role of T lymphocytes activated by Cx43 in 17β-estradiol-mediated protection against renal IRI. Female rats were classified into six groups: control rats, I/R rats, ovariectomized rats, ovariectomized I/R rats, and ovariectomized rats treated with 17β-estradiol or gap27. Levels of serum creatinine (Scr) and blood urea nitrogen (BUN) and Paller scoring were dramatically increased in I/R rats, especially in ovariectomized rats. By contrast, these indicators were markedly decreased by administering estradiol or gap27. Immunofluorescence staining revealed that CD4⁺ T cells infiltrated kidney tissues in the early stage of IRI. In both peripheral blood and renal tissue, the proportion of CD3⁺CD4⁺ T cells and ratio of CD4⁺ to CD8⁺ were high in I/R rats, especially in ovariectomized rats. The proportion of CD3⁺CD8⁺ T cells was low in peripheral blood but high in renal tissues. Administration of estrogen or Gap27 reversed these effects. IL-17 levels in both serum and tissue homogenate were significantly increased in ovariectomized rats subjected to I/R but significantly decreased in estrogen or gap 27 treated rats. The opposite trend was observed for IL-10 levels. Correlation analysis demonstrated that IL-17 was correlated positively with BUN, Scr, and Paller scores, while IL-10 was negatively correlated with these indicators. Western blot showed that Cx43 expression was markedly increased in the peripheral blood T lymphocytes of I/R rats, especially ovariectomized rats. After intervention with estrogen and gap27, Cx43 expression was significantly downregulated. These findings indicate that Cx43 may participate in the regulation of Th17/Treg balance by estrogen against renal IRI.

A Working Hypothesis Regarding Identical Pathomechanisms between Clinical Efficacy and Adverse Reaction of Clozapine via the Activation of Connexin43

Clozapine (CLZ) is an approved antipsychotic agent for the medication of treatment-resistant schizophrenia but is also well known as one of the most toxic antipsychotics. Recently, the World Health Organization’s (WHO) global database (VigiBase) reported the relative lethality of severe adverse reactions of CLZ. Agranulocytosis is the most famous adverse CLZ reaction but is of lesser lethality compared with the other adverse drug reactions of CLZ. Unexpectedly, VigiBase indicated that the prevalence and relative lethality of pneumonia, cardiotoxicity, and seizures associated with CLZ were more serious than that of agranulocytosis. Therefore, haematological monitoring in CLZ patients monitoring system provided success in the prevention of lethal adverse events from CLZ-induced agranulocytosis. Hereafter, psychiatrists must amend the CLZ patients monitoring system to protect patients with treatment-resistant schizophrenia from severe adverse CLZ reactions, such as pneumonia, cardiotoxicity, and seizures, according to the clinical evidence and pathophysiology. In this review, we discuss the mechanisms of clinical efficacy and the adverse reactions of CLZ based on the accumulating pharmacodynamic findings of CLZ, including tripartite synaptic transmission, and we propose suggestions for amending the monitoring and medication of adverse CLZ reactions associated with pneumonia, cardiotoxicity, and seizures.

Carbenoxolone decreases monocrotaline‑induced pulmonary inflammation and pulmonary arteriolar remodeling in rats by decreasing the expression of connexins in T lymphocytes

The adaptive immune response mediated by T lymphocytes is a well-established factor in the pathogenesis of pulmonary inflammation. Changes in the expression of various connexins (Cxs) or disruption of connexin-mediated cellular communication in T lymphocytes contribute to inflammation or tissue remodeling. The aim of the present study was to investigate the potential therapeutic value of blocking Cxs in a monocrotaline (MCT)-induced pulmonary inflammation rat model. Carbenoxolone (CBX) was used to inhibit connexin-mediated cellular communication. An MCT rat model was established by intraperitoneal (i.p.) injection of a single dose of MCT (60 mg/kg), and CBX treatment (20 µg/kg/day, i.p.) was initiated on the day following MCT treatment for 28 days. Vehicle-treated male Sprague-Dawley rats were used as the negative control. The MCT rat model was evaluated by measuring the pulmonary artery flow acceleration time and right ventricular hypertrophy index (RVHI). Histopathological features of the lung tissues and pulmonary arteriolar remodeling were assessed. The proportions of T lymphocyte subtypes, Cx40/cx43 expression in the T cell subtypes and the cytokine levels in the plasma and the lung tissues were also analyzed. Pharmacological inhibition of Cxs using CBX attenuated MCT-induced right ventricular hypertrophy, pulmonary arteriolar remodeling, lung fibrosis and inflammatory cell infiltration by decreasing the RVHI, pulmonary arterial wall thickening, collagen deposition and pro-inflammatory cytokines production as well as CD3⁺ and CD4⁺ T cell accumulation in lung tissues of MCT-treated rats. Furthermore, flow cytometry analysis revealed that CBX may inhibit MCT-induced Cx40 and Cx43 expression in CD4⁺ and CD8⁺ T lymphocytes in lung tissues. The present study provides evidence that pharmacological inhibition of Cxs may attenuate MCT-induced pulmonary arteriolar remodeling and pulmonary inflammatory response, at least in part, by decreasing Cx expression. The results highlight the critical role of Cxs in T lymphocytes in the MCT-induced pulmonary inflammatory response and that targeting of Cxs may be a potential therapeutic method for treating pulmonary inflammatory diseases.