High autophagic activity in podocytes, terminally differentiated cells which serve as main components of the kidney filtration barrier, is essential for podocyte survival under various challenges. How podocytes maintain such a high level of autophagy, however, remains unclear. Here we report that signal regulatory protein α (SIRPα) plays a key role in promoting podocyte autophagy. Unlike other glomerular cells, podocytes strongly express SIRPα, which is, however, downregulated in patients with focal segmental glomerulosclerosis and mice with experimental nephropathy. Podocyte SIRPα levels are inversely correlated with the severity of podocyte injury and proteinuria but positively with autophagy. Compared to wild-type littermates, Sirpa-deficient mice display greater age-related podocyte injury and proteinuria and develop more rapid and severe renal injury in various models of experimental nephropathy. Mechanistically, podocyte SIRPα strongly reduces Akt/GSK-3β/β-catenin signaling, leading to an increase in autophagic activity. Our findings thus demonstrate a critical protective role of SIRPα in podocyte survival via maintaining autophagic activity.
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http://dx.doi.org/10.1172/jci.insight.124747 | DOI Listing |
Breast Cancer Res
December 2024
School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, New Taipei City, Taiwan.
Autophagy, a crucial process in cancer, is closely intertwined with both tumor progression and drug resistance development. However, existing methods used to assess autophagy activity often pose invasiveness and time-related constraints, limiting their applicability in preclinical drug investigations. In this study, we developed a non-invasive autophagy detection system (NIADS-autophagy, also called G-cleave LC3B biosensor) by integrating a split-luciferase-based biosensor with an LC3B cleavage sequence, which swiftly identified classic autophagic triggers, such as Earle's Balanced Salt Solution and serum deprivation, through protease-mediated degradation pathways.
View Article and Find Full Text PDFOncol Res
December 2024
Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China.
Background: Triple-negative breast cancer (TNBC), characterized by its lack of traditional hormone receptors and HER2, presents a significant challenge in oncology due to its poor response to conventional therapies. Autophagy is an important process for maintaining cellular homeostasis, and there are currently autophagy biomarkers that play an effective role in the clinical treatment of tumors. In contrast to targeting protein activity, intervention with protein-protein interaction (PPI) can avoid unrelated crosstalk and regulate the autophagy process with minimal interference pathways.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Respiratory Medicine, Hunan Provincial People's Hospital (The First-Affiliated Hospital of Hunan Normal University), No. 61 Jiefang Xi Road, Changsha, Hunan, 410219, China.
Pulmonary arterial hypertension (PAH) is a serious medical condition that causes a failure in the right heart. Two-pore channel 2 (TPC2) is upregulated in PAH, but its roles in PAH remain largely unknown. Our investigation aims at the mechanisms by which TPC2 regulates PAH development.
View Article and Find Full Text PDFPhytomedicine
December 2024
Department of Oral and Maxillofacial Surgery, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, China; Department of Oral and Maxillofacial-Head Neck Oncology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; Research Unit of Oral and Maxillofacial Regenerative Medicine, Chinese Academy of Medical Sciences, Shanghai 200011, China. Electronic address:
Background: Oral squamous cell carcinoma (OSCC) is one of the most common malignancies. However, there is no effective treatment for OSCC.
Purpose: This study aimed to identify a natural compound with significant efficacy against OSCC and elucidate its primary mechanism of action.
Curr Issues Mol Biol
November 2024
Department of Anatomy and Neurosciences, School of Medicine, Eulji University, Daejeon 34824, Republic of Korea.
Ischemic stroke is a leading contributor to death and disability worldwide, driving extensive research into pharmacological treatments beyond thrombolysis. Macrophage migration inhibitory factor (MIF), a cytokine, is implicated in several pathological conditions. In this study, we examined the effects of MIF on autophagy in astrocytes under the condition of chemical hypoxia.
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