A Chemical Strategy for the Degradation of the Main Protease of SARS-CoV-2 in Cells.

SARS-CoV-2 is the virus that causes the global pandemic of COVID-19. The main protease (Mpro) of SARS-CoV-2 is essential for viral infection and is one of the major therapeutic targets for COVID-19. Here, we report the design, synthesis, and biological characterization of a novel heterobifunctional small molecule that could effectively induce the degradation of SARS-CoV-2 Mpro and its drug-resistant mutants in HEK 293T cells, thus demonstrating a new alternative strategy for intervening with proteins important for this novel coronavirus.

Increased Ca2 + transport across the mitochondria-associated membranes by Mfn2 inhibiting endoplasmic reticulum stress in ischemia/reperfusion kidney injury.

Renal ischemia/reperfusion (I/R) injury, which leads to acute kidney injury (AKI), is a major cause of morbidity and mortality in a variety of clinical situations. This study aimed to investigate the protective role of Mfn2 during renal I/R injury. Overexpression of Mfn2 in NRK-52E rat renal tubular epithelial cells and rats, then we constructed hypoxia reoxygenation (H/R) cells and I/R rat model. Apoptosis, ROS, ATP, Ca2+ levels in cells and rats, as well as renal tissue and functional injury in rats were detected respectively. Endoplasmic reticulum (ER) stress was further examined in cells and rats. The morphological changes of mitochondria-associated ER membranes (MAMs) were also detected. Mfn2 expression is reduced in H/R-treated NRK-52E cells and renal tissue of I/R rats. At the cellular level, overexpression of Mfn2 promoted cell proliferation, inhibited cell apoptosis, attenuated mitochondrial damage and Ca2+ overload, and ER stress. In addition, Mfn2 also restored the MAMs structure. In vivo experiments found that overexpression of Mfn2 could improve renal function and alleviate tissue injury. Concomitant with elevated Mfn2 expression in the kidney, reduced renal cell apoptosis, restored mitochondrial function, and reduced calcium overload. Finally, ER stress in rat kidney tissue was alleviated after overexpression of Mfn2. These results reveal that Mfn2 contributes to ER stress, mitochondrial function, and cell death in I/R injury, which provides a novel therapeutic target for AKI.

CXCR4 Recognition by L- and D-Peptides Containing the Full-Length V3 Loop of HIV-1 gp120.

Human immunodeficiency virus-1 (HIV-1) recognizes one of its principal coreceptors, CXC chemokine receptor 4 (CXCR4), on the host cell via the third variable loop (V3 loop) of HIV-1 envelope glycoprotein gp120 during the viral entry process. Here, the mechanism of the molecular recognition of HIV-1 gp120 V3 loop by coreceptor CXCR4 was probed by synthetic peptides containing the full-length V3 loop. The two ends of the V3 loop were covalently linked by a disulfide bond to form a cyclic peptide with better conformational integrity. In addition, to probe the effect of the changed side-chain conformations of the peptide on CXCR4 recognition, an all-D-amino acid analog of the L-V3 loop peptide was generated. Both of these cyclic L- and D-V3 loop peptides displayed comparable binding recognition to the CXCR4 receptor, but not to another chemokine receptor, CCR5, suggesting their selective interactions with CXCR4. Molecular modeling studies revealed the important roles played by many negative-charged Asp and Glu residues on CXCR4 that probably engaged in favorable electrostatic interactions with the positive-charged Arg residues present in these peptides. These results support the notion that the HIV-1 gp120 V3 loop-CXCR4 interface is flexible for ligands of different chiralities, which might be relevant in terms of the ability of the virus to retain coreceptor recognition despite the mutations at the V3 loop.

Discovery of Potential Inhibitors of SARS-CoV-2 Main Protease by a Transfer Learning Method.

The COVID-19 pandemic caused by SARS-CoV-2 remains a global public health threat and has prompted the development of antiviral therapies. Artificial intelligence may be one of the strategies to facilitate drug development for emerging and re-emerging diseases. The main protease (Mpro) of SARS-CoV-2 is an attractive drug target due to its essential role in the virus life cycle and high conservation among SARS-CoVs. In this study, we used a data augmentation method to boost transfer learning model performance in screening for potential inhibitors of SARS-CoV-2 Mpro. This method appeared to outperform graph convolution neural network, random forest and Chemprop on an external test set. The fine-tuned model was used to screen for a natural compound library and a de novo generated compound library. By combination with other in silico analysis methods, a total of 27 compounds were selected for experimental validation of anti-Mpro activities. Among all the selected hits, two compounds (gyssypol acetic acid and hyperoside) displayed inhibitory effects against Mpro with IC50 values of 67.6 µM and 235.8 µM, respectively. The results obtained in this study may suggest an effective strategy of discovering potential therapeutic leads for SARS-CoV-2 and other coronaviruses.

The expression of apoptosis related genes in HK-2 cells overexpressing PPM1K was determined by RNA-seq analysis.

Chronic kidney disease (CKD) is a serious disease that endangers human health. It is reported that inhibiting renal cell apoptosis can delay the progress of CKD. Our previous study found that the mice with protein phosphatase Mg2+/Mn2+ dependent 1K (PPM1K) gene deletion had obvious symptoms of glomerular vascular and interstitial vascular dilatation, congestion and hemorrhage, glomerular hemorrhage and necrosis, interstitial fibrous tissue proliferation, decreased urinary creatinine clearance, and increased urinary protein level. In addition, studies have found that PPM1K is essential for cell survival, apoptosis and metabolism. However, no study has confirmed that PPM1K can inhibit renal cell apoptosis. In this study, PPM1K was overexpressed in human kidney-2 cells (HK-2), and the biological process of differentially expressed genes and its effect on apoptosis were comprehensively screened by RNA sequencing (RNA-seq). Through sequencing analysis, we found that there were 796 differentially expressed genes in human renal tubular epithelial cells transfected with PPM1K gene, of which 553 were down-regulated and 243 were up-regulated. Enrichment analysis found that differentially expressed genes may play an important role in amino acid metabolism and biosynthesis. In the GO analysis functional pathway list, we also found that multiple genes can be enriched in apoptosis related pathways, such as G0S2, GADD45A, TRIB3, VEGFA, NUPR1 and other up-regulated genes, and IL-6, MAGED1, CCL2, TP53INP1 and other down-regulated genes. Then we verified these differentially expressed genes by RT-PCR, and found that only the RT-PCR results of G0S2, VEGFA and NUPR1 were consistent with the transcriptome sequencing results. We believe that G0S2, VEGFA, NUPR1 and other genes may participate in the apoptosis process of HK-2 cells induced by PPM1K.In conclusion, these findings provide some data support for the study of HK-2 cell apoptosis mechanism, and also provide a scientific theoretical basis for further study of the effect of PPM1K on kidney disease.

The discovery of 1, 3-diamino-7H-pyrrol[3, 2-f]quinazoline compounds as potent antimicrobial antifolates.

The shortage of new antibiotics makes infections caused by gram-negative (G-) bacteria a significant clinical problem. The key enzymes involved in folate biosynthesis represent important targets for drug discovery, and new antifolates with novel mechanisms are urgently needed. By targeting to dihydrofolate reductase (DHFR), a series of 1,3-diamino-7H-pyrrol[3,2-f]quinazoline (PQZ) compounds were designed, and exhibited potent antibacterial activities in vitro, especially against multi-drug resistant G- strains. Multiple experiments indicated that PQZ compounds contain a different molecular mechanism against the typical DHFR inhibitor, trimethoprim (TMP), and the thymidylate synthase (TS) was identified as another potential but a relatively weak target. A significant synergism between the representative compound, OYYF-175, and sulfamethoxazole (SMZ) was observed with a strong cumulative and significantly bactericidal effect at extremely low concentrations (2 µg/mL for SMZ and 0.03 pg/mL for OYYF-175), which could be resulted from the simultaneous inhibition of dihydropteroate synthase (DHPS), DHFR and TS. PQZ compounds exhibited therapeutic effects in a mouse model of intraperitoneal infections caused by Escherichia coli (E. coli). The co-crystal structure of OYYF-175-DHFR was solved and the detailed interactions were provided. The inhibitors reported represent innovative chemical structures with novel molecular mechanism of action, which will benefit the generation of new, efficacious bactericidal compounds.

Development of small molecule inhibitors targeting TGF-ß ligand and receptor: Structures, mechanism, preclinical studies and clinical usage.

Transforming growth factor-ß (TGF-ß) is a member of a superfamily of pleiotropic proteins that regulate multiple cellular processes such as growth, development and differentiation. Following binding to type I and II TGF-ß serine/threonine kinase receptors, TGF-ß activates downstream signaling cascades involving both SMAD-dependent and -independent pathways. Aberrant TGF-ß signaling is associated with a variety of diseases, such as fibrosis, cardiovascular disease and cancer. Hence, the TGF-ß signaling pathway is recognized as a potential drug target. Various organic molecules have been designed and developed as TGF-ß signaling pathway inhibitors and they function by either down-regulating the expression of TGF-ß or by inhibiting the kinase activities of the TGF-ß receptors. In this review, we discuss the current status of research regarding organic molecules as TGF-ß inhibitors, focusing on the biological functions and the binding poses of compounds that are in the market or in the clinical or pre-clinical phases of development.

Recombinant expression and biochemical characterization of Mycobacterium tuberculosis 3Fe-4S ferredoxin Rv1786.

Ferredoxins are iron-sulfur protein that mediate electron transfer in cytochrome P450 mono-oxygenase (CYP)-related catalytic reactions in a wide variety of organisms. Rv1786 is a putative ferredoxin, encoded by a gene located downstream of the gene encoding CYP143A1 in the Mycobacterium tuberculosis genome. However, the structure and function of Rv1786 have remained unclear. Here, the recombinant Mtb Rv1786 was expressed, purified as a His-tagged form and characterized with [3Fe-4S] clusters as its cofactors using a series of measurements including SDS-PAGE, western blot, UV/Visible, MALDI-TOF/TOF-MS, and electron paramagnetic resonance spectroscopic analysis. Based on the assessments of surface plasmon resonance (SPR) and steady state kinetic assays, Rv1786 was found to be able to couple with both ferredoxin reductase A (FdrA) and flavoprotein reductase A (FprA) as redox partner, but with a stronger binding to FprA and a better coupling activity to FdrA. Preliminary structural and biochemical characterization of Mtb Rv1786 as a redox partner is presented here.

[The incidence and risk factors of acute renal injury in patients with multiple soft tissue injuries].

OBJECTIVE: To investigate the incidence and risk factors of acute kidney injury (AKI) in patients with multiple soft tissue contusion. METHODS: A total of 513 patients diagnosed as multiple soft tissue contusion in the First Affiliated Hospital of Xinjiang Medical University from January 1, 2008 to January 1, 2013 were retrospectively analyzed. Demographics, clinical data and laboratory examinations before and after AKI were collected and analyzed. RESULTS: The age of all subjects was 31.30(12-78) years old with the male to female ratio of 2.1: 1. AKI occurred in 74 cases with an incidence rate of 14.4%. No AKI was observed in patients with assault injuries, while AKI was found in 27 cases (36.5%) with car accident injuries and 4 cases (5.4%) with other injuries. AKI showed in 1 case(1.4%) with damaged area under 1%, in 4 cases (5.4%) with damaged area ranged from 1% to <3%, 10 cases (13.5%) with damaged area ranged from 3% to 5% and 19 cases (25.7%) with damaged area over 5% with significant difference among the groups (P < 0.01). Incidence rate of AKI was significantly higher in patients with chronic kidney disease (CKD) than those without CKD (54.5% vs 20.3%, P < 0.01). Two of the AKI cases died, with a mortality rate of 2.7%. Multivariate logistic regression analysis showed that the followings were the independent risk factors for the occurrence of AKI in patients with multiple soft tissue injuries: age (OR = 1.996), basic serum creatinine (OR = 0.976), basic evaluated GFR (eGFR) (OR = 0.964), serum potassium (OR = 2.117), myoglobin (OR = 0.950) and damaged area (OR = 1.811). CONCLUSIONS: Incidence rate of AKI is quite high in multiple soft tissue contusion. Age, basic serum creatinine, basic eGFR, serum potassium, myoglobin and damaged area are the independent risk factors for the occurrence of AKI in patients with multiple soft tissue injury.

[The initial CT findings in patients suffering from invasive pulmonary aspergillosis].

OBJECTIVE: To approach the initial CT findings of invasive pulmonary aspergillosis (IPA) in patients with immunosuppression. METHODS: All consecutive adult patients who met the diagnostic criteria of the 2008 European Organization for Research and Treatment of Cancer/ Mycoses Study Group (EORTC/MSG) for proven or probable IPA were included as of January 2005 to June 2011. The patients were divided into two groups according to patients with or without hematological malignancy. The initial CT findings in our study were retrospectively reviewed by two thoracic radiologists, while patients' demographics and clinical outcomes were blinded. The pattern and number of abnormalities were recorded. RESULTS: A total of 65 IPA patients were eligible, with 34 hematological malignancy patients and 31 non-hematological patients. Among all IPA patients, the pattern of ground-glass opacity and consolidation or mass formation was most commonly seen (56.9%), followed by macronodules (46.2%); halo sign (32.3%) was relatively uncommon. Ground-glass opacity and consolidation or mass formation were more commonly identified in non-hematological patients than in hematological malignancy patients (54.8%, 45.2% vs. 8.8%, both P<0.05), but macronodules, infarct-shaped macronodules and halo signs were less frequently identified in the non-hematological group (16.1%, 3.2%, 12.9%, respectively) than in the hematological malignancy group (73.5%, 23.5% and 50.0%, respectively, P<0.05 or P<0.01). The airway-invasive form of IPA was more frequently seen in non-hematological patients (67.8%), whereas the angioinvasive form was more common in hematological malignancy patients (64.7%, P<0.01). CONCLUSION: Our data indicate that CT findings of IPA in non-hematological patients more commonly present as the airway-invasive form, manifesting ground-glass opacity and consolidation or mass formation, whereas in patients with hematological malignancy it more likely shows evidence of the angioinvasive form with macronodules and halo signs.

[The prevalence and risk factors of coronary heart disease combined with chronic kidney disease].

OBJECTIVE: To investigate the prevalence rate and risk factors of inpatients with coronary atherosclerotic heart disease (CHD) combined chronic kidney disease (CKD). METHODS: All people who underwent CHD combined CKD in CHD department of the First Affiliated Hospital of Xinjiang Medical University during January to December 2009 were enrolled in the retrospective study. RESULTS: A total of 960 hospitalized patients with CHD were enrolled during the observation period. The prevalence of proteinuria and reduced eGFR were 11.04% and 10.52%, respectively. The total CKD prevalence rate was 16.77%, with male of 16.67% and female of 17.11%. There was no significant difference in prevalence rate between male and female (P > 0.05). The multi-factors logistic regression analysis showed that diabetes mellitus (OR 2.60, 95%CI 1.17 - 3.29) was risk factor for CHD combined proteinuria. Ten-years older in age (OR 1.55, 95%CI 1.31 - 1.83), diabetes mellitus (OR 1.69, 95%CI 1.15 - 2.47), hypercholesterolemia (OR 2.89, 95%CI 1.49 - 5.61), and hyperuricemia (OR 1.49, 95%CI 0.96 - 2.33) were risk factors for CHD combined CKD. CONCLUSION: More attention should be paid to the high prevalence of CHD combined CKD.

[The association between chronic periodontitis and hypertension in rural adult Uygur residents].

OBJECTIVE: To explore the association between chronic periodontitis and hypertension in rural adult Uygur residents. METHODS: A total of 1415 Uygur residents aged 18 and over were selected by random multistage and probability proportional to size from 364 villages in Moyu county of Xinjiang Uygur autonomous region, all subjects received questionnaire, physical examination and biochemical analysis and oral examination. The subjects were categorized as periodontitis group and no periodontitis group, the periodontitis group was further categorized as mild, moderate and severe periodontitis subgroup. The relationship between chronic periodontitis with hypertension was analyzed by Spearman correlation. Binary logistic regression was used to calculate the influential factors for hypertension. RESULTS: The prevalence rates of chronic periodontitis and hypertension were 66.0% (934/1415) and 33.8% (478/1415), respectively. The prevalence rates of hypertension were 18.7% (90/481), 35.1% (131/373), 32.3% (62/192), 52.8% (195/369) in no periodontitis, mild, moderate and severe periodontitis groups, respectively. Spearman correlation showed an association of chronic periodontitis with hypertension (r(s) = 0.273, P < 0.01). After adjustment for age, gender, body mass index, waist circumference, glycometabolism disorder, hyperlipidemia, chronic kidney disease, multiple logistic regression analysis showed that periodontitis was significantly associated with hypertension (OR = 1.75, 95%CI: 1.30 - 2.36, P < 0.01). Compared with no periodontitis, mild (OR = 1.76, 95%CI: 1.26 - 2.48, P < 0.01) and severe (OR = 2.26, 95%CI: 1.57 - 3.26, P < 0.01) periodontitis were significantly associated with hypertension while moderate periodontitis was not significantly associated with hypertension (OR = 1.21, 95%CI: 0.80 - 1.84, P > 0.05). CONCLUSION: This study showed an independent association of periodontitis with hypertension in this study cohort.

[Epidemiology of cardiovascular risk in Chinese chronic kidney disease patients].

OBJECTIVE: To identify the risk factors associated with cardiovascular disease (CVD) in Chinese chronic kidney disease (CKD) patients. METHODS: As part of a multicenter Chinese cohort study, the clinical data associated with CVD of 1239 patients with CKD (stage 2 - 5) hospitalized in 7 grade 3A hospitals distributed in 5 regions of China 2002 - 2003 were collected. Logistic regression model was used to analyze the association between CVD and the demographic variables, lifestyle, medical history, medication, physical examination, and laboratory variables. RESULTS: (1) Increase of serum C-reactive protein (CRP, cut off > 10 mg/L) was an independent risk factor for development of coronary artery disease (CAD) (OR 2.13; 95% confidence interval [CI], 1.32 - 3.43). 21.5% of the patients in this group showed a value of CRP > 10 mg/L. (2) Being female, anemia, and systolic hypertension were the major determinants of the development of left ventricular hypertrophy (OR 2.99, CI 2.09 - 4.26; OR 2.66, CI 1.19 - 3.57; and OR 1.02, CI 1.00 to -1.02). 54.2% of the patients in this group had their systolic pressure controlled under 140mmHg, and only 15% of the patients in this group had their hemoglobin remain at the level >or= 110 g/L. (3) There was a significant interaction between the calcium-phosphate product and congestive heart failure (CHF) (OR 1.023, CI 1.01 - 1.03). 25.9% of the patients in this cohort had their calcium-phosphate product >or= 55. (4) Hypoalbuminemia (OR 6.01, CI 1.25 - 28.96) and diastolic hypertension (OR 1.05, CI 1.00 - 1.09) played major role in determining cerebrovascular accidents (CVA). In these cohort the prevalence of hypoalbuminemia was 37.3%. (5) Diabetes was associated with CAD (OR 2.34), CHF (OR 1.97), and CVA (OR 4.40), although its prevalence was lower in Chinese CKD patients (20%). Age was the risk factors of CAD (OR 1.04) and CVA (OR 1.22). Hypertension was associated with LVH (OR 1.016), CHF (OR 1.02), and CVA (OR 1.04). CONCLUSION: CKD is associated with nontraditional risk factors for the development of CVD, including chronic inflammation, malnutrition and calcium-phosphate disorders. Particular care must be taken to give optimal treatment for the most important CVD risk factors active in Chinese CKD patients, e.g. anemia and hypertension.

[Cardiovascular disease in Chinese chronic renal insufficiency patients-epidemiology survey].

OBJECTIVE: Cardiovascular (CV) disease (CVD) is the single most important cause of death among Chinese dialysis patients, accounting for 51% of overall mortality. The study was performed to investigate the prevalence and the spectrum of CVD in Chinese chronic kidney disease (CKD) patients. METHODS: The multicenter Chinese cohort study examined 1239 CKD patients from 7 main medical centers (distributed in 5 regions of China) who were hospitalized between 2002 and 2003. RESULTS: (1) The most prevalent pathological form of CVD was left ventricular (LV) hypertrophy (LVH), accounting for 58.5% of total patients. The prevalence of coronary artery disease (CAD), congestive heart failure (CHF), and cerebrovascular accidents (CVA) was 16.5%, 27.7% and 5.6%, separately. (2) The cohort with minor renal dysfunction (stage 2-3) had higher prevalence of CAD (5.9%) and CVA (1.0%) compared with general population in the same regions. Up to 41.2% of minor CKD patients were complicated with LVH, and 13.8% of them had clinical evidence of CHF. The prevalence of CAD, LVH and CHF increased as glomerular filtration decline. (3) The prevalence of CAD (20.0%) was much lower and the prevalence of CVA (5.4%) was higher in Chinese dialysis patients than that in American dialysis population. There was significant geographical variations in CAD prevalence, but it was not different between genders. CONCLUSION: The CV risk is significantly increased in patients with CKD. Even minor CKD has a major impact on the CV risk. The prevalence of CAD in Chinese dialysis patients is markedly lower than that in American dialysis population.