Dopamine receptors, including D1- and D2-like receptors, are important therapeutic targets in a variety of neurological syndromes, as well as cardiovascular and kidney diseases. Here, we present five cryoelectron microscopy (cryo-EM) structures of the dopamine D1 receptor (DRD1) coupled to Gs heterotrimer in complex with three catechol-based agonists, a non-catechol agonist, and a positive allosteric modulator for endogenous dopamine. These structures revealed that a polar interaction network is essential for catecholamine-like agonist recognition, whereas specific motifs in the extended binding pocket were responsible for discriminating D1- from D2-like receptors. Moreover, allosteric binding at a distinct inner surface pocket improved the activity of DRD1 by stabilizing endogenous dopamine interaction at the orthosteric site. DRD1-Gs interface revealed key features that serve as determinants for G protein coupling. Together, our study provides a structural understanding of the ligand recognition, allosteric regulation, and G protein coupling mechanisms of DRD1.

2021-02-10

Cell

West China Hospital, SCU

A 19-year-old woman who was 34 weeks pregnant presented at The Affiliated Hospital of Southwest Medical University (Luzhou, China) in September, 2018, with a 3-day history of abdominal pain, accompanied by vomiting and constipation. Physical examination revealed hyperpigmented macules on her lips ( figure, A), and an abdominal bulge, abdominal tenderness, and hyperactive bowel sounds. A non-contrast CT scan indicated the presence of intussusception ( figure, B) and intrauterine late pregnancy. The patient reported that her mother had undergone bowel resection twice because of intussusception and died of intestinal cancer.

2019-12-20

The Lancet. Oncology

Affiliated Hospital of Southwest Medical University

Clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas) systems in bacteria and archaea provide adaptive immunity against invading foreign nucleic acids. Previous studies suggest that certain bacteria employ their Type II CRISPR-Cas systems to target their own genes, thus evading host immunity. However, whether other CRISPR-Cas systems have similar functions during bacterial invasion of host cells remains unknown. Here we identify a novel role for Type I CRISPR-Cas systems in evading host defenses in Pseudomonas aeruginosa strain UCBPP-PA14. The Type I CRISPR-Cas system of PA14 targets the mRNA of the bacterial quorum-sensing regulator LasR to dampen the recognition by toll-like receptor 4, thus diminishing the pro-inflammatory responses of the host in cell and mouse models. Mechanistically, this nuclease-mediated RNA degradation requires a "5'-GGN-3'" recognition motif in the target mRNA, and HD and DExD/H domains in Cas3 of the Type I CRISPR-Cas system. As LasR and Type I CRISPR-Cas systems are ubiquitously present in bacteria, our findings elucidate an important common mechanism underlying bacterial virulence.

2016-12-26

Cell research

Affiliated Hospital of Southwest Medical University

Importance: Although corticosteroids are widely used for adults with sepsis, both the overall benefit and potential risks remain unclear. Objective: To conduct a systematic review and meta-analysis of the efficacy and safety of corticosteroids in patients with sepsis. Data sources and study selection: MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials were searched from inception until March 20, 2018, and updated on August 10, 2018. The terms corticosteroids, sepsis, septic shock, hydrocortisone, controlled trials, and randomized controlled trial were searched alone or in combination. Randomized clinical trials (RCTs) were included that compared administration of corticosteroids with placebo or standard supportive care in adults with sepsis. Data extraction and synthesis: Meta-analyses were conducted using a random-effects model to calculate risk ratios (RRs) and mean differences (MDs) with corresponding 95% CIs. Two independent reviewers completed citation screening, data abstraction, and risk assessment. Main outcomes and measures: Twenty-eight-day mortality. Results: This meta-analysis included 37 RCTs (N = 9564 patients). Eleven trials were rated as low risk of bias. Corticosteroid use was associated with reduced 28-day mortality (RR, 0.90; 95% CI, 0.82-0.98; I2 = 27%) and intensive care unit (ICU) mortality (RR, 0.85; 95% CI, 0.77-0.94; I2 = 0%) and in-hospital mortality (RR, 0.88; 95% CI, 0.79-0.99; I2 = 38%). Corticosteroids were significantly associated with increased shock reversal at day 7 (MD, 1.95; 95% CI, 0.80-3.11) and vasopressor-free days (MD, 1.95; 95% CI, 0.80-3.11) and with ICU length of stay (MD, -1.16; 95% CI, -2.12 to -0.20), the sequential organ failure assessment score at day 7 (MD, -1.38; 95% CI, -1.87 to -0.89), and time to resolution of shock (MD, -1.35; 95% CI, -1.78 to -0.91). However, corticosteroid use was associated with increased risk of hyperglycemia (RR, 1.19; 95% CI, 1.08-1.30) and hypernatremia (RR, 1.57; 95% CI, 1.24-1.99). Conclusions and relevance: The findings suggest that administration of corticosteroids is associated with reduced 28-day mortality compared with placebo use or standard supportive care. More research is needed to associate personalized medicine with the corticosteroid treatment to select suitable patients who are more likely to show a benefit.

2019-02-01

JAMA Intern Med

West China Hospital, SCU

Although many studies on the COVID-19 epidemic in China have been published since the outbreak began, very few, if not none, have been useful to real-time epidemic control. None have proposed methods to identify areas at risk or to allocate (or reallocate) scarce health-care resources at a fine enough scale to effectively inform epidemic control on the ground. This situation is common to many infectious diseases, particularly epidemics, which have become increasingly multifactorial and dynamic as a result of rapid urbanisation, population growth and mobility, globalisation of travel and trade, and climate change.

2020-06-01

The Lancet. Global health

West China Fourth Hospital