Synaptotagmin-3 interactions with GluA2 mediate brain damage and impair functional recovery in stroke.

Synaptotagmin III (Syt3) is a Ca2+-dependent membrane-traffic protein that is highly concentrated in synaptic plasma membranes and affects synaptic plasticity by regulating post-synaptic receptor endocytosis. Here, we show that Syt3 is upregulated in the penumbra after ischemia/reperfusion (I/R) injury. Knockdown of Syt3 protects against I/R injury, promotes recovery of motor function, and inhibits cognitive decline. Overexpression of Syt3 exerts the opposite effects. Mechanistically, I/R injury augments Syt3-GluA2 interactions, decreases GluA2 surface expression, and promotes the formation of Ca2+-permeable AMPA receptors (CP-AMPARs). Using a CP-AMPAR antagonist or dissociating the Syt3-GluA2 complex via TAT-GluA2-3Y peptide promotes recovery from neurological impairments and improves cognitive function. Furthermore, Syt3 knockout mice are resistant to cerebral ischemia because they show high-level expression of surface GluA2 and low-level expression of CP-AMPARs after I/R. Our results indicate that Syt3-GluA2 interactions, which regulate the formation of CP-AMPARs, may be a therapeutic target for ischemic insults.

GluA1 Degradation by Autophagy Contributes to Circadian Rhythm Effects on Cerebral Ischemia Injury.

The mechanisms of many diseases, including central nervous system disorders, are regulated by circadian rhythms. The development of brain disorders such as depression, autism, and stroke is strongly associated with circadian cycles. Previous studies have shown that cerebral infarct volume is smaller at night (active phase) than during the day (inactive phase) in ischemic stroke rodent models. However, the underlying mechanisms remain unclear. Increasing evidence suggests that glutamate systems and autophagy play important roles in the pathogenesis of stroke. Here, we report that GluA1 expression was decreased and autophagic activity was increased in active-phase male mouse models of stroke compared with the inactive-phase models. In the active-phase model, induction of autophagy decreased the infarct volume, whereas inhibition of autophagy increased the infarct volume. Meanwhile, GluA1 expression was decreased following activation of autophagy and increased following inhibition of autophagy. We used Tat-GluA1 to uncouple p62, an autophagic adapter, from GluA1 and found that this blocked the degradation of GluA1, an effect similar to that of inhibition of autophagy in the active-phase model. We also demonstrated that knock-out of the circadian rhythm gene Per1 abolished the circadian rhythmicity of the volume of infarction and also abolished GluA1 expression and autophagic activity in wild-type (WT) mice. Our results suggest an underlying mechanism by which the circadian rhythm participates in the autophagy-dependent regulation of GluA1 expression, which influences the volume of infarction in stroke.SIGNIFICANCE STATEMENT Circadian rhythms affect the pathophysiological mechanisms of disease. Previous studies suggested that circadian rhythms affect the infarct volume in stroke, but the underlying mechanisms remain largely unknown. Here, we demonstrate that the smaller infarct volume after middle cerebral artery occlusion/reperfusion (MCAO/R) during the active phase is related to lower GluA1 expression and activation of autophagy. The decrease in GluA1 expression during the active phase is mediated by the p62-GluA1 interaction, followed by direct autophagic degradation. In short, GluA1 is the substrate of autophagic degradation, which mainly occurs after MCAO/R during the active phase but not the inactive phase.

Is Age ≥ 55 years an optimal cutoff point among patients with differentiated thyroid Microcarcinoma? a preliminary study.

PURPOSE: Age ≥ 55 years is regarded as a pivotal component of TNM stage classification in differentiated thyroid carcinoma (DTC). However, whether this cutoff point is still adaptable for differentiated thyroid microcarcinoma (DTMC) is rarely investigated. METHODS: We reviewed and analyzed the data of DTC patients aged ≥ 55 years from the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate Cox regression analyses were used to determine the potential risk factors of cancer-specific survival (CSS) in DTMC patients aged ≥ 55 years. The Kaplan-Meier survival curves were used to estimate CSS probability. Receiver operating characteristic (ROC) curves were used to analyze the best age cutoff point for DTMC. RESULTS: Among the DTMC patients, there was no significant difference in the 1-, 3-, 5-, and 7-year CSS probability between the 55-59 years and 60-64-years subgroup (p = 0.72). The ROC curves indicated that 65 years, 65 years, and 64 years were the cutoff age point of 3-, 5-, and 7-year CSS probability in DTMC patients, respectively. Besides, N1b (Hazard ratio (HR) = 3.90, 95% Confidence interval (CI): 2.01-7.57; p < 0.001), extrathyroidal extension (HR = 2.53, 95 %CI: 1.39-4.62; p = 0.002), and M1 (HR = 11.42, 95 %CI: 5.04-25.90; p < 0.001) were the independent risk factors in CSS of DTMC patients. CONCLUSIONS: Our results suggested age at diagnosis ≥ 55 years is not the best cutoff point in stratifying the stage of the DTMC patients. On the contrary, those patients aged above 65 years have a significantly lower probability of CSS, which perhaps should be taken into consideration for treatment decision-making.

Safety and Immunogenicity of Inactivated and Recombinant Protein SARS-CoV-2 Vaccines in Patients With Thyroid Cancer.

Background: This study aimed at assessing the safety and immunogenicity of SARS-CoV-2 vaccines in patients with thyroid cancer. Methods: This observational study included thyroid cancer patients between April 1, 2021, and November 31, 2021, in the Second Affiliated Hospital of Chongqing Medical University. All participants received at least one dose of the SARS-CoV-2 vaccine. SARS-CoV-2 IgG was tested, and the interval time between the last dose and humoral response test ranged from <1 to 8 months. The complications after SARS-CoV-2 vaccines were recorded. Results: A total of 115 participants at least received one dose of SARS-CoV-2 vaccines with a 67.0% IgG-positive rate. Among them, 98 cases had completed vaccination, and the positivity of SARS-CoV-2 IgG antibodies was 96% (24/25) with three doses of ZF2001. SARS-CoV-2 IgG antibodies' positivity was 63.0% (46/73) of two doses of CoronaVac or BBIBP-CorV vaccine. Additionally, after 4 months of the last-dose vaccination, the IgG-positive rate (31.6%, 6/19) significantly decreased in thyroid cancer patients. The IgG-positive rate (81.0%, 64/79) was satisfactory within 3 months of the last-dose vaccination. Ten (10.2%) patients had side effects after SARS-CoV-2 vaccination. Among them, two (2.0%) patients had a fever, five (5.1%) patients had injection site pain, one (1.0%) patient felt dizzy, and one patient felt dizzy and had injection site pain at the same time. Conclusion: SARS-CoV-2 vaccines (CoronaVac, BBIBP-CorV, and ZF2001) are safe in thyroid cancer patients. The regression time of SARS-CoV-2 IgG is significantly shorter in thyroid cancer patients than in healthy adults. Therefore, a booster vaccination dose may be earlier than the systematic strategy for thyroid cancer patients.

Identifying and Validating of an Autophagy-Related Gene Signature for the Prediction of Early Relapse in Breast Cancer.

BACKGROUND: Compelling evidence has demonstrated the pivotal role of autophagy in the prognosis of breast cancer. Breast cancer (BC) patients with early relapse consistently exhibited worse survival. METHODS: The autophagy-related genes were derived from the Human Autophagy Database (HADb) and high-sequencing data were obtained from The Cancer Genome Atlas (TCGA). Discrepantly expressed autophagy genes (DEAGs) between early relapse and long-term survival groups were performed using the Linear Models for Microarray data (LIMMA) method. Lasso Cox regression analysis was conducted for the selection of the 4-gene autophagy-related gene signature. GSE42568 and GSE21653 databases were enrolled in this study for the external validation of the signature. Then patients were divided into high and low-risk groups based on the specific score formula. GSEA was used to discover the related signaling pathway. The Kaplan-Meier curves and the receiver operating characteristic (ROC) curves were used to evaluate the discrimination and accuracy of the 4-gene signature. RESULTS: A signature composed of four autophagy-related mRNA including APOL1, HSPA8, SIRT1, and TP73, was identified as significantly associated with the early relapse in BC patients. Time-dependent receiver-operating characteristic at 1 year suggested remarkable accuracy of the signature [area under the curve (AUC = 0.748)]. The risk score model based on the autophagy-related signature showed favorable predicting value in 1-, 2-, and 3-year relapse-free survival (RFS) in training and two validating cohorts. The GSEA displayed gene sets were remarkably enriched in carcinogenic activation pathways and autophagy-related pathways. The nomogram involving three variables (progesterone receptor status, T stage, and 4-gene signature) exhibited relatively good discrimination with a C-index of 0.766. CONCLUSIONS: Our study establishes an autophagy-related 4-gene signature that can effectively stratify the high-risk and low-risk BC patients for early relapse. Combined with the clinicopathological variables, the signature could significantly help oncologists tailor more efficient treatment strategies for BC patients.

miR-381 suppresses C/EBPα-dependent Cx43 expression in breast cancer cells.

Cx43 (connexin43) is an enhancer of the metastasis of breast cancer cells. Our previous study identified miR-381 as an indirect suppressor of Cx43 gene expression, with the precise mechanism being not understood. In the present study, using a reporter gene assay, we found that miR-381 suppressed Cx43 gene expression via the promoter region -500/-250. With site-directed gene mutation, we demonstrated that miR-381 could directly bind with the sequences CACUUGUAU in the 3'-UTR so as to inhibit C/EBPα (CCAAT/enhancer-binding protein α) expression. C/EBPα was further identified as a novel transcription factor by binding to a canonic element (AATTGTC) locating at -459/-453 in the promoter region of the Cx43 gene. Functionally, we demonstrated that miR-381 suppressed C/EBPα- and Cx43-dependent migration and invasion of breast cancer cells. Finally, we revealed that decreased levels of miR-381 as well as increased expression of C/EBPα and Cx43 in the metastatic breast cancer cells and tissues. Therefore we are the first to identify that miR-381 suppresses C/EBPα-dependent Cx43 expression in breast cancer cells. The miR-381-C/EBPα-Cx43 axis might be a useful diagnostic and therapeutic target of metastatic breast cancer.

Identification of miR-200a as a novel suppressor of connexin 43 in breast cancer cells.

Both miRNAs (miRs) and connexin 43 (Cx43) were important regulators of the metastasis of breast cancer, whereas the miRs regulating Cx43 expression in breast cancer cells were still obscure. In the present study, we scanned and found miR-1, miR-206, miR-200a, miR-381, miR-23a/b and miR-186 were functional suppressors of human Cx43 mRNA and protein expression. Specially, we demonstrated that only miR-200a could directly target the 3'-untranslated region (3'-UTR) of human Cx43 gene. Functionally, overexpression of Cx43 in MCF cells potentiated the migration activity, whereas additional miR-200a treatment notably prevented this effect. Finally, we demonstrated that decreased levels of miR-200a and elevated expression of Cx43 in the metastatic breast cancer tissues compared with the primary ones. Thus, we are the first to identify miR-200a as a novel and direct suppressor of human Cx43, indicating that miR200a/Cx43 axis might be a useful diagnostic and therapeutic target of metastatic breast cancer.