MEK1/2-PKM2 Pathway Modulates the Immunometabolic Reprogramming of Proinflammatory Allograft-infiltrating Macrophages During Heart Transplant Rejection.

BACKGROUND: Emerging evidence has highlighted the role of macrophages in heart transplant rejection (HTR). However, the molecular signals modulating the immunometabolic phenotype of allograft-infiltrating macrophages (AIMs) during HTR remain unknown. METHODS: We analyzed single-cell RNA sequencing data from cardiac graft-infiltrating immunocytes to characterize the activation patterns and metabolic features of AIMs. We used flow cytometry to determine iNOS and PKM2 expression and MEK/ERK signaling activation levels in AIMs. We then generated macrophage-specific Mek1/2 knockout mice to determine the role of the MEK1/2-PKM2 pathway in the proinflammatory phenotype and glycolytic capacity of AIMs during HTR. RESULTS: Single-cell RNA sequencing analysis showed that AIMs had a significantly elevated proinflammatory and glycolytic phenotype. Flow cytometry analysis verified that iNOS and PKM2 expressions were significantly upregulated in AIMs. Moreover, MEK/ERK signaling was activated in AIMs and positively correlated with proinflammatory and glycolytic signatures. Macrophage-specific Mek1/2 deletion significantly protected chronic cardiac allograft rejection and inhibited the proinflammatory phenotype and glycolytic capacity of AIMs. Mek1/2 ablation also reduced the proinflammatory phenotype and glycolytic capacity of lipopolysaccharides + interferon-γ-stimulated macrophages. Mek1/2 ablation impaired nuclear translocation and PKM2 expression in macrophages. PKM2 overexpression partially restored the proinflammatory phenotype and glycolytic capacity of Mek1/2 -deficient macrophages. Moreover, trametinib, an Food and Drug Administration-approved MEK1/2 inhibitor, ameliorated chronic cardiac allograft rejection. CONCLUSIONS: These findings suggest that the MEK1/2-PKM2 pathway is essential for immunometabolic reprogramming of proinflammatory AIMs, implying that it may be a promising therapeutic target in clinical heart transplantation.

The OX40-TRAF6 axis promotes CTLA-4 degradation to augment antitumor CD8+ T-cell immunity.

Immune checkpoint blockade (ICB), including anti-cytotoxic T-lymphocyte associated protein 4 (CTLA-4), benefits only a limited number of patients with cancer. Understanding the in-depth regulatory mechanism of CTLA-4 protein stability and its functional significance may help identify ICB resistance mechanisms and assist in the development of novel immunotherapeutic modalities to improve ICB efficacy. Here, we identified that TNF receptor-associated factor 6 (TRAF6) mediates Lys63-linked ubiquitination and subsequent lysosomal degradation of CTLA-4. Moreover, by using TRAF6-deficient mice and retroviral overexpression experiments, we demonstrated that TRAF6 promotes CTLA-4 degradation in a T-cell-intrinsic manner, which is dependent on the RING domain of TRAF6. This intrinsic regulatory mechanism contributes to CD8+ T-cell-mediated antitumor immunity in vivo. Additionally, by using an OX40 agonist, we demonstrated that the OX40-TRAF6 axis is responsible for CTLA-4 degradation, thereby controlling antitumor immunity in both tumor-bearing mice and patients with cancer. Overall, our findings demonstrate that the OX40-TRAF6 axis promotes CTLA-4 degradation and is a potential therapeutic target for the improvement of T-cell-based immunotherapies.

Assessing causality between second-hand smoking and potentially associated diseases in multiple systems: A two-sample Mendelian randomization study.

INTRODUCTION: The global disease burden may be exacerbated by exposure to passive smoking (SHS), with the workplace being a primary location for such exposure. Numerous epidemiological studies have identified SHS as a risk factor for diseases affecting various systems, including cardiovascular, respiratory, immune, endocrine, and nervous systems. The conventional observational study has certain methodological constraints which can be circumvented through a Mendelian randomization (MR) study. Our MR study intends to investigate the causal link between workplace exposure to SHS and the potential associated diseases. METHODS: Summary statistics data involving European participants was sourced from three databases: the UK Biobank, the FinnGen study, and the European Bioinformatics Institute. Genetic variants linked with exposure to SHS in the workplace were identified as instrumental variables. The MR was carried out using inverse variance weighted (IVW), MR-Egger, and weighted median methods. Sensitivity tests were also undertaken within the MR to evaluate the validity of the causality. RESULTS: According to the IVW model, genetically determined atrial fibrillation (AF) and stroke [P= 6.64E-04 and 5.68E-07, odds ratio = 2.030 and 2.494, 95% confidence interval = 1.350,3.051 and 1.743,3.569] were robustly associated with exposure to SHS in the workplace. Suggestive associations were found between workplace SHS and myocardial infarction (MI), asthma, and depression. CONCLUSIONS: The MR study demonstrates that exposure to SHS in the workplace is a significant risk factor for AF and stroke in European individuals. Whether workplace exposure to SHS influences other diseases and the causality between them requires further exploration. IMPLICATIONS: This study explored the causality between exposure to SHS in the workplace and potential associated diseases in multiple systems, including MI, AF, stroke, lung cancer, asthma, allergic disease, type 2 diabetes, and depression, using a MR study. The MR study can circumvent the methodological constraints of observational studies and establish a causal relationship. The two-sample MR analysis provides evidence supporting the causal association of frequent workplace SHS with AF and stroke. Individuals exposed to SHS in the workplace may also have a heightened risk of MI, asthma, and depression. However, whether SHS affects other diseases and the causality between them requires further investigation. To our knowledge, this is the first two-sample MR study to determine the causal relationship between SHS and potential diseases. As exposure to SHS in the workplace is a prevalent issue and may contribute to a global disease burden. The reduction of exposure following the introduction of smoke-free laws has led to a decrease in the admission rate for cardiac events and an improvement in health indicators. It is crucial to further advance smoke-free policies and their implementation.

A role of inflammaging in aortic aneurysm: new insights from bioinformatics analysis.

Introduction: Aortic aneurysms (AA) are prevalent worldwide with a notable absence of drug therapies. Thus, identifying potential drug targets is of utmost importance. AA often presents in the elderly, coupled with consistently raised serum inflammatory markers. Given that ageing and inflammation are pivotal processes linked to the evolution of AA, we have identified key genes involved in the inflammaging process of AA development through various bioinformatics methods, thereby providing potential molecular targets for further investigation. Methods: The transcriptome data of AA was procured from the datasets GSE140947, GSE7084, and GSE47472, sourced from the NCBI GEO database, whilst gene data of ageing and inflammation were obtained from the GeneCards Database. To identify key genes, differentially expressed analysis using the "Limma" package and WGCNA were implemented. Protein-protein intersection (PPI) analysis and machine learning (ML) algorithms were employed for the screening of potential biomarkers, followed by an assessment of the diagnostic value. Following the acquisition of the hub inflammaging and AA-related differentially expressed genes (IADEGs), the TFs-mRNAs-miRNAs regulatory network was established. The CIBERSORT algorithm was utilized to investigate immune cell infiltration in AA. The correlation of hub IADEGs with infiltrating immunocytes was also evaluated. Lastly, wet laboratory experiments were carried out to confirm the expression of hub IADEGs. Results: 342 and 715 AA-related DEGs (ADEGs) recognized from GSE140947 and GSE7084 datasets were procured by intersecting the results of "Limma" and WGCNA analyses. After 83 IADEGs were obtained, PPI analysis and ML algorithms pinpointed 7 and 5 hub IADEGs candidates respectively, and 6 of them demonstrated a high diagnostic value. Immune cell infiltration outcomes unveiled immune dysregulation in AA. In the wet laboratory experiments, 3 hub IADEGs, including BLNK, HLA-DRA, and HLA-DQB1, finally exhibited an expression trend in line with the bioinformatics analysis result. Discussion: Our research identified three genes - BLNK, HLA-DRA, and HLA-DQB1- that play a significant role in promoting the development of AA through inflammaging, providing novel insights into the future understanding and therapeutic intervention of AA.

Immune Regulation of the Liver Through the PCSK9/CD36 Pathway During Heart Transplant Rejection.

BACKGROUND: PCSK9 (proprotein convertase subtilisin/kexin 9), which is mainly secreted by the liver, is not only a therapeutic target for hyperlipidemia and cardiovascular disease, but also has been implicated in the immune regulation of infections and tumors. However, the role of PCSK9 and the liver in heart transplant rejection (HTR) and the underlying mechanisms remain unclear. METHODS: We assessed serum PCSK9 expression in both murine and human recipients during HTR and investigated the effect of PCSK9 ablation on HTR by using global knockout mice and a neutralizing antibody. Moreover, we performed multiorgan histological and transcriptome analyses, and multiomics and single-cell RNA-sequencing studies of the liver during HTR, as well. We further used hepatocyte-specific Pcsk9 knockout mice to investigate whether the liver regulated HTR through PCSK9. Last, we explored the regulatory effect of the PCSK9/CD36 pathway on the phenotype and function of macrophages in vitro and in vivo. RESULTS: Here, we report that murine and human recipients have high serum PCSK9 levels during HTR. PCSK9 ablation prolonged cardiac allograft survival and attenuated the infiltration of inflammatory cells in the graft and the expansion of alloreactive T cells in the spleen. Next, we demonstrated that PCSK9 was mainly produced and significantly upregulated in the recipient liver, which also showed a series of signaling changes, including changes in the TNF-α (tumor necrosis factor α) and IFN-γ (interferon γ) signaling pathways and the bile acid and fatty acid metabolism pathways. We found mechanistically that TNF-α and IFN-γ synergistically promoted PCSK9 expression in hepatocytes through the transcription factor SREBP2 (sterol regulatory element binding protein 2). Moreover, in vitro and in vivo studies indicated that PCSK9 inhibited CD36 expression and fatty acid uptake by macrophages and strengthened the proinflammatory phenotype, which facilitated their ability to promote proliferation and IFN-γ production by donor-reactive T cells. Last, we found that the protective effect of PCSK9 ablation against HTR is dependent on the CD36 pathway in the recipient. CONCLUSIONS: This study reveals a novel mechanism for immune regulation by the liver through the PCSK9/CD36 pathway during HTR, which influences the phenotype and function of macrophages and suggests that the modulation of this pathway may be a potential therapeutic target to prevent HTR.

Lysosomal-associated protein transmembrane 5 ameliorates non-alcoholic steatohepatitis by promoting the degradation of CDC42 in mice.

Non-alcoholic steatohepatitis (NASH) has received great attention due to its high incidence. Here, we show that lysosomal-associated protein transmembrane 5 (LAPTM5) is associated with NASH progression through extensive bioinformatical analysis. The protein level of LAPTM5 bears a negative correlation with NAS score. Moreover, LAPTM5 degradation is mediated through its ubiquitination modification by the E3 ubquitin ligase NEDD4L. Discovered by experiments conducted on male mice, hepatocyte-specific depletion of Laptm5 exacerbates mouse NASH symptoms. In contrast, Laptm5 overexpression in hepatocytes exerts diametrically opposite effects. Mechanistically, LAPTM5 interacts with CDC42 and promotes its degradation through a lysosome-dependent manner under the stimulation of palmitic acid, thus inhibiting activation of the mitogen-activated protein kinase signaling pathway. Finally, adenovirus-mediated hepatic Laptm5 overexpression ameliorates aforementioned symptoms in NASH models.

Recovery of functional fitness, lung function, and immune function in healthcare workers with nonsevere and severe COVID-19 at 13 months after discharge from the hospital: a prospective cohort study.

OBJECTIVES: This study aimed to evaluate the recovery of functional fitness, lung function, and immune function in healthcare workers (HCWs) with nonsevere and severe COVID-19 at 13 months after discharge from the hospital. METHODS: The participants of "Rehabilitation Care Project for Medical Staff Infected with COVID-19" underwent a functional fitness test (muscle strength, flexibility, and agility/dynamic balance), lung function test, and immune function test (including cytokines and lymphocyte subsets) at 13 months after discharge. RESULTS: The project included 779 HCWs (316 nonsevere COVID-19 and 463 severe COVID-19). This study found that 29.1% (130/446) of the HCWs have not yet recovered their functional fitness. The most affected lung function indicator was lung perfusion capacity (34% with diffusion capacity for carbon monoxide-single breath <80%). The increase of interleukin-6 (64/534, 12.0%) and natural killer cells (44/534, 8.2%) and the decrease of CD3+ T cells (58/534, 10.9%) and CD4+ T cells (26/534, 4.9%) still existed at 13 months after discharge. No significant difference was found in the HCWs with nonsevere and severe COVID-19 regarding recovery of functional fitness, lung function, and immune function at 13 months after discharge. CONCLUSION: The majority of Chinese HCWs with COVID-19 had recovered their functional fitness, lung function, and immune function, and the recovery status in HCWs with severe COVID-19 is no worse than that in HCWs with nonsevere COVID-19 at 13 months after discharge from the hospital.

Targeting PCSK9 Ameliorates Graft Vascular Disease in Mice by Inhibiting NLRP3 Inflammasome Activation in Vascular Smooth Muscle Cells.

Background: Graft vascular disease (GVD), which limits the long-term survival of patients after solid-organ transplantation, is associated with both immune responses and nonimmune factors, including dyslipidemia. Recent studies have shown that inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9), a U.S. Federal Drug Administration-approved treatment for hyperlipidemia, reduces cardiovascular events, regulates inflammatory responses, and enhances the efficacy of immune checkpoint therapy in cancer treatment through a cholesterol-independent mechanism. However, whether targeting PCSK9 is a potential therapeutic strategy for GVD remains unknown. Methods: Serum samples and grafts were harvested from male mice undergoing abdominal aortic transplantation. The pathological alterations in the aortic grafts were detected by hematoxylin and eosin staining, Verhoeff's Van Gieson staining, and Masson staining. Inflammatory cell infiltration and proinflammatory cytokine expression in the aortic grafts were detected by immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. The regulatory effects of PCSK9 on vascular smooth muscle cell (VSMC) migration and proliferation were examined by transwell, EdU, and western blot assays. The effect of Evolocumab, a PCSK9 inhibitor, on GVD in humanized PCSK9 mice was also evaluated. Results: PCSK9 was upregulated in the serum, grafts, and liver of mice in the allograft group subjected to abdominal aortic transplantation. Pcsk9 knockout significantly reduced vascular stenosis, the intimal hyperplasia area and collagen deposition. Pcsk9 depletion also inhibited macrophage recruitment and the mRNA expression of proinflammatory cytokines in aortic grafts. Furthermore, Pcsk9 knockout suppressed the migration and proliferation of VSMCs, which was related to the inhibition of NLRP3 inflammasome activation. Meanwhile, Evolocumab significantly ameliorated GVD in humanized PCSK9 mice. Conclusion: PCSK9 is upregulated in a mouse model of GVD, and Pcsk9 knockout reduces vascular occlusion, suggesting that PCSK9 may be a promising target for the treatment of GVD.

Preoperative Nomogram and Risk Calculator for Postoperative Hypoxemia and Related Clinical Outcomes Following Stanford Type A Acute Aortic Dissection Surgery.

Background: Hypoxemia is a common complication after Stanford type A acute aortic dissection surgery (AADS), however, few studies about hypoxemia after AADS exist. The aims of this study were to identify independent risk factors for hypoxemia after AADS and to clarify its association with clinical outcomes. Methods: Patients undergoing AADS from 2016 to 2019 in our hospital were identified and used as a training set. Preoperative variables were first screened by univariate analysis and then entered into a multivariate logistic regression analysis to identify independent risk factors. A nomogram and an online risk calculator were constructed based on the logistic model to facilitate clinical practice and was externally validated in an independent dataset. Results: Severe hypoxemia developed in 119 of the 492 included patients (24.2%) and poorer clinical outcomes were observed in these patients. Five independent risk factors for severe hypoxemia after AADS were identified by multivariate analysis, including older age, smoking history, renal insufficiency, higher body mass index, and white blood cell count. The model showed good calibration, discrimination, and clinical utility in the training set, and was well validated in the validation set. Risk stratification was performed and three risk groups were defined as low, medium, and high risk groups. Hypertension was identified as an independent risk factor for moderate hypoxemia besides the five predictors mentioned above, and renal insufficiency was not significant for mild hypoxemia by multivariate analysis. In addition, although frozen elephant trunk was associated with increased risk of postoperative hypoxemia in the univariate analysis, frozen elephant trunk was also not identified as an independent risk factor for postoperative hypoxemia in the multivariate analysis. Conclusion: Hypoxemia was frequent following AADS, related to poorer clinical outcomes. Predictors were identified and a nomogram as well as an online risk calculator predicting severe hypoxemia after AADS was developed and validated, which may be helpful for risk estimation and perioperative management.

B-cell lymphoma 6 alleviates nonalcoholic fatty liver disease in mice through suppression of fatty acid transporter CD36.

Nonalcoholic fatty liver disease (NAFLD) is an ubiquitous disease that exists across a wide spectrum ranging from steatosis, steatohepatitis, advanced fibrosis, and liver cirrhosis. Hallmarks of NAFLD are lipid accumulation, insulin resistance, and chronic low-grade inflammation. However, there currently are no medications approved for NAFLD. B-cell lymphoma 6 (BCL6) is a transcriptional inhibitor that is vital for germinal center B-cell formation. Our study identified BCL6 as a critical modulator of hepatic lipid metabolism and appears to contribute to the initiation and progression of NAFLD. In our research, we induced hepatic BCL6 overexpression using adeno-associated virus (AAV), as well as conditional liver-specific BCL6 knockout mice (BCL6-CKO). With these models, we noted that BCL6 overexpression improved insulin resistance and hepatic steatosis in mice models maintained on a HFD diet. Conversely, these parameters worsened in the livers of mice with downregulated BCL6 levels. Mechanistically, the translocase fatty acid CD36 was determined to be a transcriptional target of BCL6 that influences its role in hepatic steatosis. BCL6 bound directly to the CD36 promoter region, restraining CD36 transcription under physiological conditions. We conclude that the hepatocyte BCL6 inhibits the NAFLD progression in mice, including deranged lipid accumulation and glucose metabolism, through a CD36-dependent manner. These results indicate that BCL6 may potentially be targeted in NAFLD treatment.

Ablation of Survivin in T Cells Attenuates Acute Allograft Rejection after Murine Heterotopic Heart Transplantation by Inducing Apoptosis.

Although studies in oncology have well explored the pharmacological effects of Birc5, little is known about its role in allogeneic T-cell responses. Therefore, the present study used a mouse model of acute heart allograft rejection to investigate the protective effect and mechanism of conditional knockout of Birc5 in T cells. Survivin (encoded by Birc5) was up-regulated in T cells activated in vivo and in vitro. Deletion of Birc5 in T cells attenuated acute heart allograft rejection by reducing the ratio of effector to naive T cells and Th1 to Tregs. In addition, deletion of Birc5 had no noticeable effect on proliferation but on apoptosis and the secretion of IFN-γ. The results revealed a significant increase in the percentage of Annexin V positive CD4+ T cells in the Birc5-/- group, compared to the WT. Moreover, there was significant increase in early apoptotic alloreactive T cells in Birc5-/- mice and this was partly mediated by caspase-3. Furthermore, treatment with YM155 inhibited acute heart allograft rejection in vivo and increased T-cell apoptosis in healthy human PBMCs in vitro. The results highlight a potential therapeutic target for the prevention and treatment of acute transplant rejection.

Dynamic changes of functional fitness, antibodies to SARS-CoV-2 and immunological indicators within 1 year after discharge in Chinese health care workers with severe COVID-19: a cohort study.

BACKGROUND: Few studies had described the health consequences of patients with coronavirus disease 2019 (COVID-19) especially in those with severe infections after discharge from hospital. Moreover, no research had reported the health consequences in health care workers (HCWs) with COVID-19 after discharge. We aimed to investigate the health consequences in HCWs with severe COVID-19 after discharge from hospital in Hubei Province, China. METHODS: We conducted an ambidirectional cohort study in "Rehabilitation Care Project for Medical Staff Infected with COVID-19" in China. The participants were asked to complete three physical examinations (including the tests of functional fitness, antibodies to SARS-CoV-2 and immunological indicators) at 153.4 (143.3, 164.8), 244.3 (232.4, 259.1), and 329.4 (319.4, 339.3) days after discharge, respectively. Mann-Whitney U test, Kruskal-Wallis test, t test, one-way ANOVA, χ2, and Fisher's exact test were used to assess the variance between two or more groups where appropriate. RESULTS: Of 333 HCWs with severe COVID-19, the HCWs' median age was 36.0 (31.0, 43.0) years, 257 (77%) were female, and 191 (57%) were nurses. Our research found that 70.4% (114/162), 48.9% (67/137), and 29.6% (37/125) of the HCWs with severe COVID-19 were considered to have not recovered their functional fitness in the first, second, and third functional fitness tests, respectively. The HCWs showed improvement in muscle strength, flexibility, and agility/dynamic balance after discharge in follow-up visits. The seropositivity of IgM (17.0% vs. 6.6%) and median titres of IgM (3.0 vs. 1.4) and IgG (60.3 vs. 45.3) in the third physical examination was higher than that in the first physical examination. In the third physical examination, there still were 42.1% and 45.9% of the HCWs had elevated levels of IL-6 and TNF-α, and 11.9% and 6.3% of the HCWs had decreased relative numbers of CD3+ T cells and CD4+ T cells. CONCLUSION: The HCWs with severe COVID-19 showed improvement in functional fitness within 1 year after discharge, active intervention should be applied to help their recovery if necessary. It is of vital significance to continue monitoring the functional fitness, antibodies to SARS-CoV-2 and immunological indicators after 1 year of discharge from hospital in HCWs with severe COVID-19.

Dual-Specificity Phosphatase 26 Protects Against Cardiac Hypertrophy Through TAK1.

Background Heart pathological hypertrophy has been recognized as a predisposing risk factor for heart failure and arrhythmia. DUSP (dual-specificity phosphatase) 26 is a member of the DUSP family of proteins, which has a significant effect on nonalcoholic fatty liver disease, neuroblastoma, glioma, and so on. However, the involvement of DUSP26 in cardiac hypertrophy remains unclear. Methods and Results Our study showed that DUSP26 expression was significantly increased in mouse hearts in response to pressure overload as well as in angiotensin II-treated cardiomyocytes. Cardiac-specific overexpression of DUSP26 mice showed attenuated cardiac hypertrophy and fibrosis, while deficiency of DUSP26 in mouse hearts resulted in increased cardiac hypertrophy and deteriorated cardiac function. Similar effects were also observed in cellular hypertrophy induced by angiotensin II. Importantly, we showed that DUSP26 bound to transforming growth factor-ß activated kinase 1 and inhibited transforming growth factor-ß activated kinase 1 phosphorylation, which led to suppression of the mitogen-activated protein kinase signaling pathway. In addition, transforming growth factor-ß activated kinase 1-specific inhibitor inhibited cardiomyocyte hypertrophy induced by angiotensin II and attenuated the exaggerated hypertrophic response in DUSP26 conditional knockout mice. Conclusions Taken together, DUSP26 was induced in cardiac hypertrophy and protected against pressure overload induced cardiac hypertrophy by modulating transforming growth factor-ß activated kinase 1-p38/ c-Jun N-terminal kinase-signaling axis. Therefore, DUSP26 may provide a therapeutic target for treatment of cardiac hypertrophy and heart failure.

Managements of 13 emergency cardiac surgeries under COVID-19 pandemic in a Sentinel Hospital.

BACKGROUND: The pneumonia outbreak caused by the 2019 novel coronavirus disease (COVID-19) creates many challenges for the healthcare sector. Currently, little is known of how the pandemic has impacted patients with cardiovascular disease. The primary focus of this study was to determine whether emergency cardiovascular surgeries can be carried out safely during the COVID-19 pandemic. METHODS: Between 17 January 2020 and 11 February 2020, 13 patients were admitted to Wuhan Union Hospital for emergency cardiovascular surgery. During this time, Wuhan was a COVID-19 epicenter, and Wuhan Union Hospital is a sentinel hospital located in this area. These patients' epidemiological histories, clinical records, laboratory assessments, imaging findings, and surgical outcomes were retrospectively reviewed. Throat swabs were collected from some patients preoperatively and all patients postoperatively for reverse transcription polymerase chain reaction (RT-PCR) testing to determine whether these patients had COVID-19. RESULTS: This cohort included 5 cases of acute aortic dissection, 3 cases of congenital heart disease, 2 cases of dilated cardiomyopathy with end-stage heart failure, 1 case of aortocoronary fistula that had undergone previous surgery, 1 case of subacute infective endocarditis with cerebral infarction, and 1 case of multivessel coronary disease. Six patients were suspected COVID-19 cases (46.2%). There were no confirmed COVID-19 cases in this cohort. None of the patients in this cohort died and none developed severe acute respiratory syndrome, renal failure, or septic shock after surgery. No cross-infection occurred with other patients or medical staff who came into close contact with this cohort. CONCLUSIONS: Emergency surgery is crucial and unavoidable for many patients with acute and severe cardiovascular disease, regardless of the pandemic. Our study indicates that, with adequate preparation and the provision of appropriate treatment, satisfactory outcomes can be achieved for such patients.

Early outcomes of Stanford type A aortic dissection under the coronavirus disease 2019 (COVID-19) pandemic: a multicentre study from Hubei province.

OBJECTIVES: Our goal was to compare the short-term outcomes of Stanford type A aortic dissection (TAAD), during the coronavirus disease 2019 (COVID-19) pandemic with those during normal times and summarize our perioperative management experience of patients with TAAD in the context of COVID-19. METHODS: From 17 January 2020 to 8 March 2020, a total of 27 patients with TAAD were operated on in 8 cardiovascular surgery centres in Hubei Province (COVID-19 group). The data from 91 patients with TAAD from the same centres during the same period last year were extracted from the Hubei Cardiac Surgery Registration System (control group). A propensity score matched subgroup of 26 pairs (1:2) was identified. Perioperative data and short-term outcomes were assessed. RESULTS: Nine patients in the COVID-19 group were categorized as suspicious for the disease (9/27, 33.3%), and others were excluded (18/27, 66.7%). No one was laboratory confirmed preoperatively. The average waiting, cross-clamp and circulatory arrest times were longer in the COVID-19 group (22.9 ± 8.3 vs 9.7 ± 4.0 h, P < 0.001; 135 ± 36 vs 103 ± 45 min, P = 0.003; 24 ± 9 vs 17 ± 8 min, P < 0.001, respectively). The 30-day or in-hospital deaths were 3.8% in both groups (P = 1.0). The COVID-19 group was associated with longer ventilation and intensive care unit times (81 ± 71 vs 45 ± 19 h, P < 0.001; 7.4 ± 3.8 vs 4.5 ± 2.7 days; P < 0.001, respectively). There were no statistical differences between the 2 groups in the incidence of complications such as stroke, neurological deficit, acute kidney injury, pulmonary infection and reoperation. Serum antibody tests for those patients showed 7 out of 9 suspected cases were Immunoglobulin G positive. No cross-infection occurred in other patients or associated medical staff. CONCLUSIONS: With adequate preparation and appropriate protection, satisfactory early outcomes can be achieved after emergency operations for patients with TAAD during the COVID-19 pandemic.

Autophagy-lysosome inhibitor chloroquine prevents CTLA-4 degradation of T cells and attenuates acute rejection in murine skin and heart transplantation.

Background: The immune checkpoint cytotoxic T lymphocyte antigen-4 (CTLA-4), induced upon T cell activation but degraded quickly, has been targeted in the clinical therapy of advanced cancers and autoimmune diseases. However, whether inhibiting CTLA-4 degradation ameliorates transplant rejection remains unknown. Methods: The CTLA-4 expression in activated murine T cells treated with the inhibitors mediating protein degradation was detected by flow cytometry (FCM). CD45.1 mice, which received TEa T cells and underwent heart transplantation, were administrated with the inhibitor. Subsequently, CTLA-4 expression of TEa T cells was analyzed. Murine skin and heart transplantation models were built, then the survival and histopathology of the allografts, and T cell subsets in the spleens of each group were compared. Results: Chloroquine (CQ) was identified as an inhibitor of CTLA-4 degradation, which augmented both surface and total CTLA-4 expression in T cells. It considerably prolonged the skin and heart allograft survival time and reduced the infiltration of inflammatory cells in allografts. Besides decreasing the frequencies of the CD4+ and CD8+ effector T cells, especially IFN-γ producing T cells, CQ also increased the proportion of regulatory T cells in the spleen. The CTLA-4 blockade abrogated the benefits of CQ on the survival of heart allografts. Moreover, CQ enhanced CTLA-4 expression in activated human T cells and reduced the secretion of IFN-γ in human mixed lymphocyte reaction. Conclusion: Targeting CTLA-4 degradation provides a novel means to prevent transplant rejection and induce transplant tolerance.

PLK1 Inhibition alleviates transplant-associated obliterative bronchiolitis by suppressing myofibroblast differentiation.

Chronic allograft dysfunction (CAD) resulting from fibrosis is the major limiting factor for long-term survival of lung transplant patients. Myofibroblasts promote fibrosis in multiple organs, including the lungs. In this study, we identified PLK1 as a promoter of myofibroblast differentiation and investigated the mechanism by which its inhibition alleviates transplant-associated obliterative bronchiolitis (OB) during CAD. High-throughput bioinformatic analyses and experiments using the murine heterotopic tracheal transplantation model revealed that PLK1 is upregulated in grafts undergoing CAD as compared with controls, and that inhibiting PLK1 alleviates OB in vivo. Inhibition of PLK1 in vitro reduced expression of the specific myofibroblast differentiation marker α-smooth muscle actin (α-SMA) and decreased phosphorylation of both MEK and ERK. Importantly, we observed a similar phenomenon in human primary fibroblasts. Our results thus highlight PLK1 as a promising therapeutic target for alleviating transplant-associated OB through suppression of TGF-ß1-mediated myofibroblast differentiation.

PKM2 Activator TEPP-46 Attenuates Thoracic Aortic Aneurysm and Dissection by Inhibiting NLRP3 Inflammasome-Mediated IL-1ß Secretion.

BACKGROUND: The development of thoracic aortic aneurysm and dissection (TAAD) is mediated by inflammasome activation, which exacerbates the secretion of pro-inflammatory cytokines, chemokines, matrix metalloproteinases (MMPs), and reactive oxygen species (ROS). The glycolytic enzyme pyruvate kinase M2 (PKM2) has shown a protective role against various disorders with an inflammatory basis, such as sepsis, tumorigenesis, and diabetic nephropathy. However, its potential role in TAAD has not been investigated so far. APPROACH AND RESULTS: We analyzed aortic tissues from TAAD patients and the ß-aminopropionitrile fumarate (BAPN)-induced mouse model of TAAD and observed elevated levels of PKM2 in the aortic lesions of both. Treatment with the PKM2 activator TEPP-46 markedly attenuated the progression of TAAD in the mouse model as demonstrated by decreased morbidity and luminal diameter of the aorta. In addition, the thoracic aortas of the BAPN-induced mice showed reduced monocytes and macrophages infiltration and lower levels of IL-1ß, MMPs, and ROS when treated with TEPP-46. Furthermore, TEPP-46 treatment also suppressed the activation of the NOD-like receptor (NLR) family and pyrin domain-containing protein 3 (NLRP3) inflammasome by downregulating p-STAT3 and HIF1-α. CONCLUSION: Pyruvate kinase M2 plays a protective role in TAAD development, and its activation is a promising therapeutic strategy against the progression of TAAD.

Glibenclamide ameliorates transplant-induced arteriosclerosis and inhibits macrophage migration and MCP-1 expression.

AIMS: Glibenclamide, a diabetes mellitus type 2 medication, has anti-inflammatory and autoimmune properties. This study investigated the effects of glibenclamide on transplant-induced arteriosclerosis as well as the underlying molecular events. METHODS: Male C57Bl/6 (H-2b) and BALB/c (H-2d) mice were used for aorta transplantation. We used hematoxylin and eosin (HE) and Elastic Van Gieson (EVG) staining for histological assessment, and qRT-PCR and ELISA to measure mRNA and protein levels. Mouse peritoneal macrophages were isolated for lipopolysaccharide (LPS) stimulation and glibenclamide treatment followed by ELISA, Western blot, and Transwell assays. RESULTS: Glibenclamide inhibited transplant-induced arteriosclerosis in vivo. Morphologically, glibenclamide reduced inflammatory cell accumulation and collagen deposition in the aortas. At the gene level, glibenclamide suppressed aortic cytokine mRNA levels, including interleukin-1ß (IL-1ß; 10.64 ± 3.19 vs. 23.77 ± 5.72; P < .05), tumor necrosis factor-α (TNF-α; 4.59 ± 0.78 vs. 13.89 ± 5.42; P < .05), and monocyte chemoattractant protein-1 (MCP-1; 202.66 ± 23.44 vs. 1172.73 ± 208.80; P < .01), while IL-1ß, TNF-α, and MCP-1 levels were also reduced in the mouse sera two weeks after glibenclamide treatment (IL-1ß, 39.40 ± 13.56 ng/ml vs. 78.96 ± 9.39 ng/ml; P < .01; TNF-α, 52.60 ± 13.00 ng/ml vs. 159.73 ± 6.76 ng/ml; P < .01; and MCP-1, 56.60 ± 9.07 ng/ml vs. 223.07 ± 36.28 ng/ml; P < .001). Furthermore, glibenclamide inhibited macrophage expression and secretion of inflammatory factors in vitro through suppressing activation of the nuclear factor-κB (NF-κB) pathway and MCP-1 production. CONCLUSION: Glibenclamide protected against aorta transplantation-induced arteriosclerosis by reducing inflammatory factors in vivo and inhibited macrophage migration and MCP-1 production in vitro.