Lactic acid (LA) accumulation in tumor microenvironments (TME) has been implicated in immune suppression and tumor progress. Diverse roles of LA have been elucidated, including microenvironmental pH regulation, signal transduction, post-translational modification, and metabolic remodeling. This review summarizes LA functions within TME, focusing on the effects on tumor cells, immune cells, and stromal cells. Reducing LA levels is a potential strategy to attack cancer, which inevitably affects the physiological functions of normal tissues. Alternatively, transporting LA into the mitochondria as an energy source for immune cells is intriguing. We underscore the significance of LA in both tumor biology and immunology, proposing the burning of LA as a potential therapeutic approach to enhance antitumor immune responses.
Humans ; Tumor Microenvironment/immunology* ; Neoplasms/therapy* ; Lactic Acid/immunology* ; Mitochondria/metabolism* ; Animals ; Signal Transduction

OBJECTIVE To establish a mouse model of diabetes mellitus(DM)combined with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection to investigate the important pathophysiological changes in the development of DM combined with SARS-CoV-2 infection.METHODS Wild-type(WT)mice and transgenic mice expressing the human angiotensin-converting enzyme 2 receptor driven by the cytokeratin-18 gene promoter(K18-hACE2)were randomly divided into the control group,DM group,SARS-CoV-2 spike protein(S)infection group and DM combined with S protein infection group,with 10 to 12 mice in each group.All the mice were induced by 10 weeks of high-fat diet combined with 40 mg·kg-1 streptozotocin(STZ)for 3 days by ip,except those in the control group or S protein infection group.The control group was given the same volume of 0.1 mol·L-1 sodium citrate buffer.Mice in the S protein infection group and DM+S protein infection group were additionally given 50 μL mixture of 15 μg SARS-CoV-2 spike protein and 1 g·L-1 polyinosinic-polycytidylic acid(poly[I:C])via intranasal drops,while the control group was given an equal volume of sterile water.The glucose tolerance level and pancreatic islet β cell function of mice were evaluated via oral glucose tolerance test at the 6th week of high-fat feeding and 1 week after the administration of STZ by ip.From the 6th week of high-fat feeding to 2 weeks after the administration of STZ,the random blood glucose and fasting blood glucose of mice were measured by a blood glucose meter.Blood samples were taken from subman-dibular veins of 3 mice in each group at 24,48 and 120 h after S protein infection,and lung tissues were taken after euthanization.The pathological changes of lungs of DM mice before and after S protein infection were observed by HE staining.Except for the DM group,blood samples were collected before S protein infection and at 6,24,48,72 and 120 h after infection.The levels of plasma interleukin 1β(IL-1β),IL-2,IL-6,IL-10,IL-17,interferon gamma-induced protein 10(IP-10),interferon γ(IFN-γ),tumor necrosis factor α(TNF-α),monocyte chemotactic protein-1(MCP-1)and granulocyte-colony stimulating factor(G-CSF)were detected by Luminex.The plasma levels of heparan sulfate(HS)were measured by enzyme-linked immunosorbent assay.The levels of cytokines and HS were correlated with the degree of pathological damage by Spearman correlation analysis.RESULTS STZ and high-fat diet could induce DM-like expression in mice,and the random blood glucose(P<0.01)and fasting blood glucose(P<0.05)after 1 week in the hACE2-DM group were significantly higher than in the WT-DM group,and the degree of islet function damage in hACE2-DM mice was significantly higher than that of WT-DM mice(P<0.05).Compared with the DM group,the DM+S group showed more severe pulmonary pathological changes after S protein infection,accompanied by a large number of inflammatory infiltrations and thickening of lung interstitial.Compared with the control group,the levels of pro-inflammatory cytokines G-CSF,IL-6 and IP-10 in the plasma of the WT-S group were significantly increased at 6 h after S pro-tein infection(P<0.01),and those of pro-inflammatory cytokine IL-17 and anti-inflammatory cytokine IL-10 were significantly increased at 24 h after S protein infection(P<0.05).Compared with the control group,the plasma levels of pro-inflammatory cytokines IL-1β,IL-6,TNF-α,MCP-1,G-CSF and IP-10 in the hACE2-S group were significantly increased at 6 h after S protein infection(P<0.05,P<0.01).IL-17 was significantly increased at 24 h and 6 h after S protein infection in the WT-DM+S group and hACE2-DM+S group,respectively(P<0.01,P<0.05).In the hACE2-DM+S group,IFN-γ and IL-1β were signifi-cantly increased in delay to 48 h(P<0.05,P<0.01),and MCP-1 was significantly increased in delay to 72h(P<0.05).Compared with the control group,the level of HS in the plasma of the WT-S group increased significantly(P<0.05,P<0.01)at 6 h and 24 h after S protein infection,but began to decrease at 48 h.At the same time,compared with the WT-S group,the HS level in the WT-DM+S group was slightly increased at 6 h after infection and decreased at 24 h.Compared with the control group,the HS level in the hACE2-S group was significantly increased at 24 h(P<0.01),as was the case with the WT-S group 24 h,48 h and 120 h after S protein infection.At 6 h,24 h and 48 h after S protein infection,the plasma HS level of the hACE2-DM+S group was significantly increased(P<0.01,P<0.05),and the duration of the increase was longer than in the hACE2-S group.Moreover,the levels of IL-1β,IL-10,MCP-1,IP-10,G-CSF and HS in plasma were positively correlated with the degree of lung dam-age in the DM+S group.CONCLUSION In this study,the mouse model of diabetes combined with SARS-CoV-2 spike protein infection has mimicked part of the pathophysiological features of clinical patients,mainly manifested as blunted immune response and elevated HS levels with longer duration to infection alone.IL-1β,IL-10,MCP-1,IP-10,G-CSF and HS may keep track of the course of disease in patients with diabetes combined with SARS-CoV-2 infection.

Objective:A SARS-CoV-2 pseudovirus(PsV)system was established for neutralizing antibody evaluation and virus entry inhibitor screening.Methods:Lentiviral vector plasmids psPAX2,pCDH-Luc and SARS-CoV-2 Spike(S)protein expres-sion plasmids were co-transfected,and harvested pseudoviral supernatant was used to infect ACE2-293T cells.Protein content of p24 was determined to reflect titer of PsV,and expression of S protein in PsV was detected by Western blot.Neutralization capacity of an S protein monoclonal antibody was evaluated using original strain,D614G,Gamma,Delta,Omicron PsV.Two reported virus entry inhibitors,chloroquine and carrageenin,were used to detect effect on entry of Omicron PsV.Results:Lentiviral vector successfully incorporated S protein.Western blot results showed that S protein mutated at 665Y showed a different cleavage form(90 kD)than wild-type full-length S protein(180 kD).Titer of PsV packaged by three plasmids system was higher.Ratio of S protein expression plasmid,transfer plasmid and packaging plasmid at 1∶3∶3 was optimum condition for viral packaging.Titer of PsV packaged under this condi-tion was over 20 ng/ml.PsV could effectively infect ACE2-293T cells,and double reporter gene GFP and firefly luciferase were expressed obviously,whose chemiluminescence values reached 106.Monoclonal antibodies of S protein effectively neutralized four types of PsVs,but neutralization of original strain was 10～30 times greater than that of variant PsV.Virus entry inhibitors,chloroquine and ι-carrageenan significantly inhibited entry of Omicron PsV.Conclusion:SARS-CoV-2 PsV infection system we conducted can simu-late entry of SARS-CoV-2 successfully.Effective pharmacodynamic evaluation of neutralizing antibodies and virus entry inhibitors can be performed efficiently by the system,which can provide a technical platform for evaluation of neutralizing antibody of SARS-CoV-2 and screening of virus entry inhibitors,and would benefit R&D of anti-SARS-CoV-2 drugs.

Background/Aims: Non-alcoholic fatty liver disease (NAFLD) is associated with the development of cardiovascular disease. While existing studies have examined cardiac remodeling in NAFLD, there has been less emphasis on the development of carotid atherosclerosis and stroke. We sought to conduct a meta-analysis to quantify the prevalence, risk factors, and degree of risk increment of carotid atherosclerosis and stroke in NAFLD. Methods: Embase and Medline were searched for articles relating to NAFLD, carotid atherosclerosis, and stroke. Proportional data was analysed using a generalized linear mixed model. Pairwise meta-analysis was conducted to obtain odds ratio or weighted mean difference for comparison between patients with and without NAFLD. Results: From pooled analysis of 30 studies involving 7,951 patients with NAFLD, 35.02% (95% confidence interval [CI], 27.36–43.53%) had carotid atherosclerosis with an odds ratio of 3.20 (95% CI, 2.37–4.32; P<0.0001). Pooled analysis of 25,839 patients with NAFLD found the prevalence of stroke to be 5.04% (95% CI, 2.74–9.09%) with an odds ratio of 1.88 (95% CI, 1.23–2.88; P=0.02) compared to non-NAFLD. The degree of steatosis assessed by ultrasonography in NAFLD was closely associated with risk of carotid atherosclerosis and stroke. Older age significantly increased the risk of developing carotid atherosclerosis, but not stroke in NAFLD. Conclusions This meta-analysis shows that a stepwise increment of steatosis of NAFLD can significantly increase the risk of carotid atherosclerosis and stroke development in NAFLD. Patients more than a third sufferred from carotid atherosclerosis and routine assessment of carotid atherosclerosis is quintessential in NAFLD.

Objective:To compare the consistency and difference of non-mydriatic two-field 45° ultra-wide field Optos and Clarus500 fundus imaging in a large-scale diabetic retinopathy (DR) screening.Methods:A diagnostic methodology study. From November 2020 to August 2021, 526 eyes of 277 patients with type 2 diabetes who diagnosed in Department of Ophthalmology, Henan Provincial People's Hospital were included in the study. Among them, there were 175 males with 328 eyes and 102 females with 198 eyes; the age was 53±10 years old. The same experienced technician performed the non-mydriatic dual-field 45° fundus imaging and the non-mydriatic ultra-wide-angle imaging system Optos, Clarus500 single-field fundus imaging examination on the patient on the same day, and obtained the dual-field 45° fundus image and Optos, Clarus500 single-field fundus image. The Optos and Clarus500 single-field fundus images in the same area as the dual-field 45° fundus image were captured by Photoshop software, and the Optos and Clarus500 dual-field fundus images were obtained. Subsequently, two experienced ophthalmologists performed interpretation and DR grading of the 5 groups of images, respectively. Images with inconsistent grading results were interpreted by a third ophthalmologist and used as the final grading result. In order to avoid the mydriatic dual-field 45° imaging interpretation results as the standard, the consistency and detection rate difference of the two ultra-wide-angle imaging systems in the rapid DR screening results were evaluated. The weighted Kappa ( κ) test was used to analyze the consistency of DR diagnosis between dual-field 45° fundus imaging and Optos and Clarus500 fundus imaging; χ2 test was used to compare the detection rates of DR between different imaging systems. Results:Compared with the dual-field 45° fundus image, the Clarus500 single-field had a higher DR detection rate ( χ2=24.965, P<0.001), and the Optos dual-field fundus image had a lower DR detection rate ( χ2=49.559, P<0.001). Compared with the DR detection rate of dual-field 45° fundus image, Optos single-field fundus image, Clarus500 double-field fundus image had no significant difference ( χ2=2.572, 0.649; P=0.109, 0.421). Compared with Optos, Clarus500 single-field and dual-field fundus images DR detection rate, the difference was statistically significant ( χ2=43.214, 61.216; P<0.001). Consistency assessment of DR grading results: dual-field 45° fundus images and Clarus500 dual-field fundus images ( κ value=0.932, 95% confidence interval ( CI) 0.907-0.956) were highly consistent; dual-field 45° fundus images and Optos single-field fundus images [ κ value=0.474, 95% CI 0.417-0.532], Optos dual-field fundus image ( κ value=0.495, 95% CI 0.438-0.551), Optos dual-field fundus image ( κ value=0.495, 95% CI 0.438-0.551) and Clarus500 dual-field fundus image ( κ value=0.452, 95% CI 0.395-0.506) were moderately consistent; dual-field 45°fundus images and Clarus500 single-field fundus images ( κ value=0.354, 95% CI 0.303-0.403) and Optos single-field fundus images and Clarus500 single-field fundus images ( κ value=0.347, 95% CI 0.287-0.393) showed general agreement. Conclusions:Compared with Optos dual-field fundus image, dual-field 45°fundus image and Clarus500 dual-field fundus image have high consistency in the grading results of DR rapid screening. Compared with Optos single-field fundus image, the detection rate of the DR of Clarus500 single-field fundus image is higher.

OBJECTIVE:To provide theoretic basis for the design and synthesis of novel high-activity biaryl aminothiazineβ-amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitor,the research and development of new AD therapy drugs. METHODS:Totally 41 molecules of biaryl aminothiazine BACE1 inhibitors were selected. By SYBYL-X 2.0 software package, CoMFA and CoMSIA method were used to construct 3D-QSAR model of derivatized compounds. Surflex-dock molecular docking was applied to analyze binding mode of the compounds with BACE1. RESULTS:The q2 value of 3D-QSAR model established by CoMFA and CoMSIA method were all higher than 0.5,indicating good predictability. The established three dimensional contour plots could manifest the effect of substituents at different sites on activity of compounds. Surflex-dock analysis showed that biaryl aminothiazine and amino acid residues as ASP80, ASP276 and TYR246 in BACE1 had a key effect on hydrogen bonds. CONCLUSIONS:3D-QSAR model established on the basis of biaryl aminothiazine derivatized compounds show good predictability,which provides guidance for the structure optimization of the compound. TYR246 may be another potential active functional residue of biaryl aminothiazine inhibitor compound molecule combined with BACE1. Through 3D-QSAR analysis and molecular docking,new biaryl aminothiazine BACE1 inhibitor can be designed and synthesized so as to research and develop new drugs for AD.