Dexamethasone rescues TGF-β1-mediated β2-adrenergic receptor dysfunction and attenuates phosphodiesterase 4D expression in human airway smooth muscle cells

Serum TGF-β as a predictive biomarker for severe disease and fatality of COVID-19

For targeted intervention in coronavirus disease 2019 (COVID-19), there is a high medical need for biomarkers that predict disease progression and severity in the first days after symptom onset. This study assessed the utility of early transforming growth factor β (TGF-β) serum levels in COVID-19 patients to predict disease severity, fatality, and response to dexamethasone therapy. Patients with severe COVID-19 had significantly higher TGF-β levels (416 pg/mL) as compared to patients with mild (165 pg/mL, p < 0.0001) or moderate COVID-19 (241 pg/mL; p < 0.0001). Receiver operating characteristics area under the curve values were 0.92 (95% confidence interval [CI] 0.85-0.99, cut-off: 255 pg/mL) for mild versus severe COVID-19, and 0.83 (95% CI 0.65-1.0, cut-off: 202 pg/mL) for moderate versus severe COVID-19. Patients who died of severe COVID-19 had significantly higher TGF-β levels (453 pg/mL) as compared to convalescent patients (344 pg/mL), and TGF-β levels predicted fatality (area under the curve: 0.75, 95% CI 0.53-0.96). TGF-β was significantly reduced in severely ill patients treated with dexamethasone (301 pg/mL) as compared to untreated patients (416 pg/mL; p < 0.05). Early TGF-β serum levels in COVID-19 patients predict, with high accuracy, disease severity, and fatality. In addition, TGF-β serves as a specific biomarker to assess response to dexamethasone treatment.

Genetic deletion of phosphodiesterase 4D in the liver improves kidney damage in high-fat fed mice: liver-kidney crosstalk

A growing body of epidemiological evidence suggests that nonalcoholic fatty liver disease (NAFLD) is an independent risk factor for chronic kidney disease (CKD), but the regulatory mechanism linking NAFLD and CKD remains unclear. Our previous studies have shown that overexpression of PDE4D in mouse liver is sufficient for NAFLD, but little is known about its role in kidney injury. Here, liver-specific PDE4D conditional knockout (LKO) mice, adeno-associated virus 8 (AAV8)-mediated gene transfer of PDE4D and the PDE4 inhibitor roflumilast were used to assess the involvement of hepatic PDE4D in NAFLD-associated renal injury. We found that mice fed a high-fat diet (HFD) for 16 weeks developed hepatic steatosis and kidney injury, with an associated increase in hepatic PDE4D but no changes in renal PDE4D. Furthermore, liver-specific knockout of PDE4D or pharmacological inhibition of PDE4 with roflumilast ameliorated hepatic steatosis and kidney injury in HFD-fed diabetic mice. Correspondingly, overexpression of hepatic PDE4D resulted in significant renal damage. Mechanistically, highly expressed PDE4D in fatty liver promoted the production and secretion of TGF-β1 into blood, which triggered kidney injury by activating SMADs and subsequent collagen deposition. Our findings revealed PDE4D might act as a critical mediator between NAFLD and associated kidney injury and indicated PDE4 inhibitor roflumilast as a potential therapeutic strategy for NAFLD-associated CKD.

Carbocistein improves airway remodeling in asthmatic mice

BACKGROUND

The alleviating effects of carbocisteine (S-carboxymethylcysteine, SCMC) have been implicated in chronic obstructive pulmonary disease; however, very little is known about its mechanisms in asthma. In this study, we aimed to investigate the effects of SCMC on airway remodeling in asthmatic mice induced by ovalbumin (OVA).

METHODS

The asthma mouse model was generated by OVA sensitization and stimulation and subsequently intervened by SCMC or dexamethasone. Bronchoalveolar lavage fluid (BALF) and lung tissues were collected from each group of mice. The TGF-β1 levels in BALF were measured by ELISA. Masson's staining was used to detect collagen fiber deposition in mouse airway tissues, while immunohistochemistry and RT-qPCR were conducted to examine the protein and mRNA expression of TGF-β1 in mouse lung airway tissues, respectively. The correlation between TGF-β1 mRNA expression and the area of collagen fiber deposition in airway tissues was analyzed by Pearson's correlation coefficient.

RESULTS

The area of collagen fiber deposition in the airway tissues of asthmatic mice was significantly increased, while SCMC alleviated the collagen fiber deposition in the airway tissues. TGF-β1 expression was significantly elevated in BALF and airway tissues of asthmatic mice, while SCMC inhibited TGF-β1 expression. TGF-β1 expression was significantly and positively correlated with collagen fiber deposition in mouse airway tissues.

CONCLUSIONS

SCMC intervention improves collagen fiber deposition in airway tissues and inhibits TGF-β1 expression in asthmatic mice.