IgE induced by type 2 immune responses in atopic dermatitis is implicated in the progression of atopic dermatitis to other allergic diseases, including food allergies, allergic rhinitis, and asthma. However, the keratinocyte-derived signals that promote IgE and ensuing allergic diseases remain unclear. Herein, in a mouse model of atopic dermatitis–like skin inflammation induced by epicutaneous Staphylococcus aureus exposure, keratinocyte release of IL‑36α along with IL-4 triggered B cell IgE class-switching, plasma cell differentiation, and increased serum IgE levels—all of which were abrogated in IL-36R–deficient mice or anti-IL‑36R–blocking antibody–treated mice. Moreover, skin allergen sensitization during S. aureus epicutaneous exposure-induced IL-36 responses was required for the development of allergen-specific lung inflammation. In translating these findings, elevated IL‑36 cytokines in human atopic dermatitis skin and in IL‑36 receptor antagonist–deficiency patients coincided with increased serum IgE levels. Collectively, keratinocyte-initiated IL‑36 responses represent a key mechanism and potential therapeutic target against allergic diseases.

The small GTPase RhoA and its downstream effectors are critical regulators in the pathophysiological processes of asthma. The underlying mechanism, however, remains undetermined. Here, we generated an asthma mouse model with RhoA–conditional KO mice ( Sftpc-cre;RhoA ^fl/fl ) in type II alveolar epithelial cells (AT2) and demonstrated that AT2 cell–specific deletion of RhoA leads to exacerbation of allergen-induced airway hyperresponsiveness and airway inflammation with elevated Th2 cytokines in bronchoalveolar lavage fluid (BALF). Notably, Sftpc-cre;RhoA ^fl/fl mice showed a significant reduction in Tgf-β1 levels in BALF and lung tissues, and administration of recombinant Tgf-β1 to the mice rescued Tgf-β1 and alleviated the increased allergic airway inflammation observed in Sftpc-cre;RhoA ^fl/fl mice. Using RNA sequencing technology, we identified Slc26a4 (pendrin), a transmembrane anion exchange, as the most upregulated gene in RhoA-deficient AT2 cells. The upregulation of SLC26A4 was further confirmed in AT2 cells of asthmatic patients and mouse models and in human airway epithelial cells expressing dominant-negative RHOA (RHOA-N19). SLA26A4 was also elevated in serum from asthmatic patients and negatively associated with the percentage of forced expiratory volume in 1 second (FEV ₁ %). Furthermore, SLC26A4 inhibition promoted epithelial TGF-β1 release and attenuated allergic airway inflammation. Our study reveals a RhoA/SLC26A4 axis in AT2 cells that functions as a protective mechanism against allergic airway inflammation.

Background: The 2019 novel coronavirus disease (COVID-19) emerged in Wuhan, Hubei province, China, and was characterized as pandemic by the World Health Organization. Diabetes mellitus is an established risk factor for poor clinical outcomes, but the association of diabetes with the prognosis of COVID-19 have not been reported yet. Methods: In this cohort study, we retrospectively reviewed 258 consecutive hospitalized COVID-19 patients with or without diabetes at the West Court of Union Hospital of Huazhong University of Science and Technology in Wuhan, China, recruited from January 29 to February 12, 2020. The cases were confirmed by real-time PCR and the demographic, clinical, laboratory, radiological, and treatment data were collected and analyzed. Prognosis was defined as hospitalization, discharged survivor and death, which was followed up until March 12, 2020. Results: Of the 258 hospitalized patients (63 with diabetes) with COVID-19, the median age was 64 years (range 23-91), and 138 (53.5%) were male. No significant differences in age and sex were identified between patients with and without diabetes. Common symptoms included fever (82.2%), dry cough (67.1%), polypnea (48.1%), and fatigue (38%). Patients with diabetes had significantly higher leucocyte and neutrophil counts, and higher levels of fasting blood glucose, serum creatinine, urea nitrogen and creatine kinase isoenzyme MB at admission compared with those without diabetes. COVID-19 patients with diabetes were more likely to develop severe or critical disease condition with more complications at presentation, and had higher incidence rates of antibiotic therapy, non-invasive and invasive mechanical ventilation, and death (11.1% vs. 4.1%). Cox proportional hazard model showed that diabetes (adjusted hazard ratio [aHR]=3.64; 95% confidence interval [CI]: 1.09, 12.21) and fasting blood glucose (aHR=1.19; 95% CI: 1.08, 1.31) were associated with the fatality of COVID-19, adjusting for potential confounders. Conclusions: Diabetes mellitus is associated with greater disease severity and a higher risk of mortality in patients with COVID-19. Primary and secondary prevention strategies are needed for COVID-19 patients with diabetes.