S-Palmitoylation during Retinoic Acid-Induced Neuronal Differentiation of SH-SY5Y Neuroblastoma Cells

Astragaloside IV-PESV facilitates pyroptosis by enhancing palmitoylation of GSDMD protein mediated by ZDHHC1

Prostate cancer (PCa) is an epithelial malignancy affecting the prostate gland. Astragaloside IV combined with polypeptide extract from scorpion venom (PESV) has been reported to inhibit the growth of PCa. This study aimed to investigate the mechanisms by which this combination mitigates the progression of PCa. Bioinformatic analysis was utilized to investigate the correlation between zinc finger DHHC-type containing 1 (ZDHHC1) expression and PCa progression. The extent of pyroptosis in PCa cells was assessed by measuring cell viability, IL-1β and IL-18 secretion, LDH release, and HMGB1 content. PCa mouse models were constructed by subcutaneous injection of DU145 or PC-3 cells into nude mice, with subsequent monitoring of tumor weight and volume. ZDHHC1 expression was significantly lower in PCa patient tissues, which correlated with a poor prognosis. ZDHHC1 overexpression inhibited PC-3 and DU145 cell viability and increased IL-1β, IL-18, LDH, and HMGB1 levels in cell supernatants. Notably, the pyroptosis inhibitor LDC7559 partially reversed these effects. Co-IP assay demonstrated an interaction between ZDHHC1 and GSDMD. ZDHHC1 overexpression significantly enhanced GSDMD palmitoylation-mediated membrane translocation and pyroptosis; however, this effect was partially reversed by the palmitoylation inhibitor 2-BP. The combination of Astragaloside IV and PESV promoted GSDMD membrane translocation and pyroptosis in PCa cells, with ZDHHC1 knockdown partially reversing the effects of Astragaloside IV-PESV. Furthermore, treatment with Astragaloside IV-PESV significantly inhibited tumor tissue growth in tumor-bearing nude mouse models. Astragaloside IV-PESV enhances palmitoylation-mediated membrane translocation of GSDMD-N by upregulating ZDHHC1 expression, thereby facilitating pyroptosis in PCa cells and attenuating PCa progression.

Protein palmitoylation: biological functions, disease, and therapeutic targets

Protein palmitoylation, a reversible post-translational lipid modification, is catalyzed by the ZDHHC family of palmitoyltransferases and reversed by several acyl protein thioesterases, regulating protein localization, accumulation, secretion, and function. Neurological disorders encompass a spectrum of diseases that affect both the central and peripheral nervous system. Recently, accumulating studies have revealed that pathological protein associated with neurological diseases, such as β-amyloid, α-synuclein, and Huntingtin, could undergo palmitoylation, highlighting the crucial roles of protein palmitoylation in the onset and development of neurological diseases. However, few preclinical studies and clinical trials focus on the interventional strategies that target protein palmitoylation. Here, we comprehensively reviewed the emerging evidence on the role of protein palmitoylation in various neurological diseases and summarized the classification, processes, and functions of protein palmitoylation, highlighting its impact on protein stability, membrane localization, protein-protein interaction, as well as signal transduction. Furthermore, we also discussed the potential interventional strategies targeting ZDHHC proteins and elucidated their underlying pathogenic mechanisms in neurological diseases. Overall, an in-depth understanding of the functions and significances of protein palmitoylation provide new avenues for investigating the mechanisms and therapeutic approaches for neurological disorders.

Protocol to identify S-acylated proteins in hippocampal neurons using ω-alkynyl fatty acid analogs and click chemistry

S-acylation, commonly palmitoylation, is the addition of fatty acids to cysteines to regulate protein localization and function. S-acylation detection has been hampered by limited sensitivity and selectivity in low-protein, costly samples like cultured neurons. Here, we present a protocol for sensitive and selective bioorthogonal labeling and click-chemistry-based detection of S-acylated proteins in primary hippocampal neurons. We describe steps for metabolically labeling neurons with alkynyl fatty acid, click chemistry, NeutrAvidin-based capture, and elution with hydroxylamine.

Mechanisms and functions of protein S-acylation

Over the past two decades, protein S-acylation (often referred to as S-palmitoylation) has emerged as an important regulator of vital signalling pathways. S-Acylation is a reversible post-translational modification that involves the attachment of a fatty acid to a protein. Maintenance of the equilibrium between protein S-acylation and deacylation has demonstrated profound effects on various cellular processes, including innate immunity, inflammation, glucose metabolism and fat metabolism, as well as on brain and heart function. This Review provides an overview of current understanding of S-acylation and deacylation enzymes, their spatiotemporal regulation by sophisticated multilayered mechanisms, and their influence on protein function, cellular processes and physiological pathways. Furthermore, we examine how disruptions in protein S-acylation are associated with a broad spectrum of diseases from cancer to autoinflammatory disorders and neurological conditions.

Temporal Quantitative Proteomic and Phosphoproteomic Profiling of SH-SY5Y and IMR-32 Neuroblastoma Cells during All-Trans-Retinoic Acid-Induced Neuronal Differentiation

The human neuroblastoma cell lines SH-SY5Y and IMR-32 can be differentiated into neuron-like phenotypes through treatment with all-trans-retinoic acid (ATRA). After differentiation, these cell lines are extensively utilized as in vitro models to study various aspects of neuronal cell biology. However, temporal and quantitative profiling of the proteome and phosphoproteome of SH-SY5Y and IMR-32 cells throughout ATRA-induced differentiation has been limited. Here, we performed relative quantification of the proteomes and phosphoproteomes of SH-SY5Y and IMR-32 cells at multiple time points during ATRA-induced differentiation. Relative quantification of proteins and phosphopeptides with subsequent gene ontology analysis revealed that several biological processes, including cytoskeleton organization, cell division, chaperone function and protein folding, and one-carbon metabolism, were associated with ATRA-induced differentiation in both cell lines. Furthermore, kinase-substrate enrichment analysis predicted altered activities of several kinases during differentiation. Among these, CDK5 exhibited increased activity, while CDK2 displayed reduced activity. The data presented serve as a valuable resource for investigating temporal protein and phosphoprotein abundance changes in SH-SY5Y and IMR-32 cells during ATRA-induced differentiation.