The renin-angiotensin system (RAS) is crucial for the physiology and pathology of all the organs. Angiotensinconverting enzyme 2 (ACE2) maintains the homeostasis of RAS as a negative regulator. Recently, ACE2 was identified as the receptor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the coronavirus that is causing the pandemic of Coronavirus disease 2019 (COVID-19). Since SARS-CoV-2 must bind with ACE2 before entering the host cells in humans, the distribution and expression of ACE2 may be critical for the target organ of the SARS-CoV-2 infection. Moreover, accumulating evidence has demonstrated the implication of ACE2 in the pathological progression in tissue injury and several chronic diseases, ACE2 may also be essential in the progression and clinical outcomes of COVID-19. Therefore, we summarized the expression and activity of ACE2 in various physiological and pathological conditions, and discussed its potential implication in the susceptibility of SARS-CoV-2 infection and the progression and prognosis of COVID-19 patients in the current review.

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The UCSF COMET Consortium, Michael Matthay, David J. E rl e , P re scot t G. Woodruff, Charles Langelier, Kirsten K an ge la ri s, C ar ol yn M.

BRCA1/2 mutation carriers who have been treated with PS have a substantially reduced breast cancer incidence and mortality. Clin Cancer Res; 22(15); 3971-81. ©2016 AACR.

Smoking-related emphysema is a chronic inflammatory disease driven by T helper 17 (TH17) cells through molecular mechanisms that remain obscure. Here we have explored the role of microRNA-22 (miR-22) in emphysema. MiR-22 was upregulated in lung myeloid dendritic cells (mDCs) of smokers with emphysema and antigen-presenting cells (APCs) of mice exposed to smoke or nanoparticulate carbon black (nCB) through a mechanism involving NF-κB. MiR-22-deficient mice, but not wild-type, showed attenuated TH17 responses and failed to develop emphysema after exposure to either smoke or nCB. We further show that miR-22 controls APC activation and TH17 responses through activation of AP-1 transcription factor complexes and histone deacetylase (HDAC) 4. Thus, miR-22 is a critical regulator of both emphysema and TH17 responses.