Calpeptin attenuates cigarette smoke-induced pulmonary inflammation via suppressing calpain/IκBα signaling in mice and BEAS-2B cells

Knockdown of RTEL1 Alleviates Chronic Obstructive Pulmonary Disease by Modulating M1, M2 Macrophage Polarization and Inflammation

Chronic obstructive pulmonary disease (COPD) is a common chronic disease characterized by airflow obstruction, which seriously threatens people's health. The COPD mouse model was established with cigarette smoke induction. Hematoxylin-eosin staining and Masson staining were carried out to observe the pathological changes of lung tissues in COPD mice. RTEL1 was silenced in COPD mice, and immunohistochemistry was used to detect RTEL1, ki67 and Caspase-3 expression. The role of RTEL1 in inflammation were evaluated by ELISA, and the impacts of RTEL1 on M1 and M2 macrophage markers (iNOS and CD206) were evaluated by qPCR and western blotting. In COPD model, there was an increase in the number of inflammatory cells, with slightly disorganized cell arrangement, unclear hierarchy, condensed and solidified nuclei, while knockdown of RTEL1 improved the inflammatory infiltration. Moreover, knockdown of RTEL1 reduced ki67-positive cells and increased Caspase-3 positive cells in COPD group. The increased inflammatory factors (IL-1β, MMP-9, TNF-α, IL-4, IL-6, and IL-23) in COPD were suppressed by knockdown of RTEL1, while iNOS was raised and CD206 was inhibited. In conclusion, knockdown of RTEL1 promoted M1 and inhibited M2 macrophage polarization and inflammation to alleviate COPD.

CAPN5 attenuates cigarette smoke extract-induced apoptosis and inflammation in BEAS-2B cells

INTRODUCTION

Apoptosis and chronic inflammation are the main phenotypes in chronic obstructive pulmonary disease (COPD) pathogenesis. Cigarette smoke exposure is the leading risk factor for COPD, which causes aberrant airway epithelial structure and function. As a non-classical calpain, the molecular function of calpain5 (CAPN5) in COPD remains unclear. This study investigated the role of CAPN5 in mediating cigarette smoke extract (CSE)-induced apoptosis and inflammation.

METHODS

Immunohistochemistry (IHC) and Western blotting (WB) were performed to detect the location and expression of CAPN5. In vitro, BEAS-2B cells were transfected with CAPN5 siRNA or CAPN5 plasmid, followed by phosphate-buffered saline (PBS) or cigarette smoke extract (CSE) treatment. The protein expression levels of CAPN5, NF-κB p65, p-p65, IκBα, p-IκBα and apoptosis proteins (BCL-2, BAX) were measured by WB. Flow cytometry (FCM) was performed to analyze the cell apoptosis index.

RESULTS

CAPN5 was mainly expressed in the airway epithelium and significantly decreased in the COPD-smoker and emphysema-mouse groups. Silencing CAPN5 significantly decreased the protein expression of BCL-2, IκBα, and increased p-p65 and BAX protein expression. Additionally, an increased apoptosis index was detected after silencing CAPN5. Moreover, overexpression of CAPN5 partly inhibited IκBα degradation and p65 activation, and reduced CSE-induced inflammation and apoptosis.

CONCLUSIONS

These combined results indicate that CAPN5 could protect against CSE-induced apoptosis and inflammation, which may provide a potential therapeutic target for smoking-related COPD.

A Putative Role for TRPC6 in Immune-Mediated Kidney Injury

Excessive activation of the immune system is the cause of a wide variety of renal diseases. However, the pathogenic mechanisms underlying the aberrant activation of the immune system in the kidneys often remain unknown. TRPC6, a member of the Ca2+-permeant family of TRPC channels, is important in glomerular epithelial cells or podocytes for the process of glomerular filtration. In addition, TRPC6 plays a crucial role in the development of kidney injuries by inducing podocyte injury. However, an increasing number of studies suggest that TRPC6 is also responsible for tightly regulating the immune cell functions. It remains elusive whether the role of TRPC6 in the immune system and the pathogenesis of renal inflammation are intertwined. In this review, we present an overview of the current knowledge of how TRPC6 coordinates the immune cell functions and propose the hypothesis that TRPC6 might play a pivotal role in the development of kidney injury via its role in the immune system.

Inhibitors of SARS-CoV-2 main protease: Biological efficacy and toxicity aspects

The emergence of the highly contagious respiratory disease, COVID-19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a significant global public health concern. To combat this virus, researchers have focused on developing antiviral strategies that target specific viral components, such as the main protease (Mpro), which plays a crucial role in SARS-CoV-2 replication. While many compounds have been identified as potent inhibitors of Mpro, only a few have been translated into clinical use due to the potential risk-benefit trade-offs. Development of systemic inflammatory response and bacterial co-infection in patients belong to severe, frequent complications of COVID-19. In this context, we analysed available data on the anti-inflammatory and antibacterial activities of the SARS-CoV-2 Mpro inhibitors for possible implementation in the treatment of complicated and long COVID-19 cases. Synthetic feasibility and ADME properties were calculated and included for better characterisation of the compounds' predicted toxicity. Analysis of the collected data resulted in several clusters pointing to the most prospective compounds for further study and design. The complete tables with collected data are attached in Supplementary material for use by other researchers.

Calpeptin may reverse glucocorticoid-resistance of allergic rhinitis associated with cigarette smoke exposure by down-regulating interferon regulatory factor 1

Cigarette smoke exposure is an important factor in chronic inflammation in patients with allergic rhinitis (AR); however, the relationship between cigarette smoke and AR-related glucocorticoid resistance requires further study. In mice, calpeptin significantly reduces inflammation of the lower respiratory tract caused by cigarette smoke, but whether it can treat glucocorticoid-resistant AR caused by cigarette smoke requires further research. In this study, we confirmed that cigarette smoke exposure can aggravate the Th2 inflammatory response in AR leading to glucocorticoid resistance. The underlying mechanism may be related to decreased expression of DNA methyltransferase 3a (Dnmt3a), and increased expression of interferon regulatory factor 1 (IRF1). In addition, we found that calpeptin can inhibit the expression of IRF1 and thus treat AR-associated glucocorticoid resistance in rats exposed to cigarette smoke. These data suggest that calpeptin may downregulate IRF1 and therefore treat glucocorticoid resistance in AR-associated with cigarette smoke exposure.

Identification of potent small molecule inhibitors of SARS-CoV-2 entry

The severe acute respiratory syndrome coronavirus 2 responsible for COVID-19 remains a persistent threat to mankind, especially for the immunocompromised and elderly for which the vaccine may have limited effectiveness. Entry of SARS-CoV-2 requires a high affinity interaction of the viral spike protein with the cellular receptor angiotensin-converting enzyme 2. Novel mutations on the spike protein correlate with the high transmissibility of new variants of SARS-CoV-2, highlighting the need for small molecule inhibitors of virus entry into target cells. We report the identification of such inhibitors through a robust high-throughput screen testing 15,000 small molecules from unique libraries. Several leads were validated in a suite of mechanistic assays, including whole cell SARS-CoV-2 infectivity assays. The main lead compound, calpeptin, was further characterized using SARS-CoV-1 and the novel SARS-CoV-2 variant entry assays, SARS-CoV-2 protease assays and molecular docking. This study reveals calpeptin as a potent and specific inhibitor of SARS-CoV-2 and some variants.

25(OH)-Vitamin D alleviates neonatal infectious pneumonia via regulating TGFβ-mediated nuclear translocation mechanism of YAP/TAZ

Neonatal infectious pneumonia (NIP) is a common infectious disease that develops in the neonatal period. The purpose of our study was to explore the potential roles of 25(OH)-Vitamin D (25-OH-VD) and its anti-inflammatory mechanism in NIP. The results showed that serum 25-OH-VD level was negatively correlated with the severity of NIP, whereas Spearman’s correlation analysis showed a significant positive correlation between the severity of NIP and the levels of pneumonia markers procalcitonin (PCT) and interleukin-6 (IL-6). The expression of vitamin D receptor (VDR) was down-regulated, while the transforming growth factor β (TGFβ), nuclear YAP, and TAZ were up-regulated in the peripheral blood mononuclear cells (PBMCs) of neonates with severe pneumonia. Neonates with 25-OH-VD deficiency were associated with an increased risk of NIP. In BEAS-2B cells, down-regulation of nuclear YAP and TAZ was found in the lipopolysaccharide (LPS) + VD group relative to the LPS-induced group. Additionally, positive rate of nuclear YAP, as detected by immunocytochemistry (ICC), and the nuclear translocation of nuclear YAP/TAZ by IFA in the LPS+VD group showed an intermediate level between that of the control and LPS-induced groups. Furthermore, the expressions of VDR and CYP27B1 were significantly increased in the LPS+VD group as compared to those in the LPS-induced group. The anti-inflammatory mechanism in NIP was achieved due to the 25-OH-VD mediating TGFβ/YAP/TAZ pathway, which suggested that using 25-OH-VD might be a potential strategy for NIP treatment.