Gadd45a Expression Research Articles

Citreoviridin induces apoptosis through oxidative damage and inflammatory response in PC-12 cells.

Citreoviridin (CIT) is a mycotoxin produced by various fungi. Although CIT has been reported to cause neurotoxicity, the molecular mechanism is poorly understood. Therefore, the aim of this study was to investigate the effects and molecular mechanisms of CIT in neurotoxicity. Different concentrations of CIT were treated to rat pheochromocytoma (PC-12 cells), and oxidative stress parameters, cytokine levels, and cell apoptosis were evaluated. CIT treatment (5 and 10μM) significantly induced PC-12 cell apoptosis and increased lactate dehydrogenase activity. Additionally, CIT treatment induced oxidative stress, as evidenced by a significant increase in intracellular levels of reactive oxygen species, malondialdehyde, and superoxide dismutase and a decrease in glutathione activity. Moreover, CIT treatment induced an inflammatory response, as evidenced by a significant increase in the intracellular levels of the proinflammatory cytokines tumor necrosis factor-alpha and interleukin-1-beta in PC-12 cells. Furthermore, quantitative PCR and western blotting showed that CIT treatment increased both the protein and mRNA expression of GADD45α and p21 in PC-12 cells, suggesting that CIT may induce apoptosis by inhibiting cell cycle, blocking cell growth, and damaging DNA. Conclusively, this study contributes the understanding the toxicity mechanisms of CIT to nerve cells.

NPS-1034 Exerts Therapeutic Efficacy in Renal Cell Carcinoma Through Multiple Targets of MET, AXL, and TNFRSF1A Signaling in a Metastatic Model.

Renal cell carcinoma (RCC) has diverse pathological subtypes, most of which have a poor prognosis. Patients with advanced RCC require systemic therapies for disease control. Although targeted therapies and immune checkpoint inhibitors have shown therapeutic efficacy, patients eventually succumb to disease progression. Therefore, additional therapies targeting different pathways are needed to provide more therapeutic options for sequential treatment. Our study explored the biological mechanisms and therapeutic outcomes for NPS-1034, a dual MET/AXL inhibitor, in RCC, both in vivo and in vitro. Our results showed that NPS-1034 can significantly inhibit tumor proliferation and induce cancer cell apoptosis. Besides MET and AXL, known targets of NPS-1034, we identified TNFRSF1A as another target gene inhibited by NPS-1034 via antibody arrays. This was further supported by next-generation sequencing, showing that the TNF signaling pathway is one of the most significant NPS-1034-regulated pathways. Furthermore, one of the identified target genes, GADD45A, responsible for NPS-1034 anticancer properties, was significantly associated with patient survival in RCC. GADD45A expression was significantly upregulated via NPS-1034 and downregulated via TNFRSF1A overexpression. Finally, its therapeutic efficacy was demonstrated in vivo, showing that NPS-1034 significantly alleviated the tumor burden and inhibited cell proliferation in a lung metastatic animal model. In conclusion, we explored the therapeutic mechanism of NPS-1034 and found that it targets not only MET and AXL but also TNFRSF1A. In a lung metastatic animal model, we confirmed that NPS-1034 is a potential candidate for systemic therapy in RCC.

Metal-Organic Framework: Fabrication of Nano Fluorescent Composite Materials and Treatment of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is a common malignant tumor originating from liver cells, characterized by complex pathogenesis and limited treatment options such as surgery, chemotherapy, and transplantation. Cisplatin, an effective chemotherapeutic agent, disrupts cancer cell DNA but is hindered by side effects and the need for controlled sustained release to optimize efficacy. Metal-organic frameworks (MOFs) have emerged as promising nanocarriers for precise local drug delivery, reducing required doses and mitigating side effects of chemotherapeutic drugs, thus offering a potential avenue for hepatocellular carcinoma (HCC) treatment. In this research, a rectangular channel MOF (Rumgay H, Ferlay J, Martel C, Georges D, Ibrahim AS, Zheng R, Wei W, Lemmens VEPP, Soerjomataram I (2022) Global, regional and national burden of primary liver cancer by subtype. Eur J Cancer 161:108-118) carrier was synthesized using ligand L as the organic linker coordinated with Cu(II) and I(I). The MOF's structure and fluorescence properties were characterized. Additionally, to enhance substrate biocompatibility, composite carrier materials were prepared by incorporating polylactic acid (PLA) with 1, utilized for cisplatin loading. To evaluate the inhibitory effect of PLA-1@cisplatin on HCC, HepG-2 and Huh-7 HCC cell lines were treated with varying concentrations of the drug for 48h, and their cell viability was assessed. The results demonstrated a significant dose-dependent reduction in cell viability of both HepG-2 and Huh-7 cells. To explore the potential inhibitory mechanism of PLA-1@cisplatin on HCC, the mRNA levels of GADD45A and NACC1 in HepG-2 and Huh-7 cells post-treatment were measured. GADD45A expression, initially low in HCC cells, was significantly upregulated after drug treatment, while NACC1, typically highly expressed in HCC, showed a significant decrease in mRNA levels with increasing concentrations of PLA-1@cisplatin. These findings indicate that PLA-1@cisplatin effectively upregulates GADD45A expression and downregulates NACC1 expression. Overall, the developed cisplatin-loaded nanoparticle system holds promise for HCC treatment by reducing chemotherapy side effects and enhancing drug efficacy.

Gadd45A-mediated autophagy regulation and its impact on Alzheimer's disease pathogenesis: Deciphering the molecular Nexus

BackgroundThe growth arrest and DNA damage-inducible 45 (Gadd45) gene has been implicated in various central nervous system (CNS) functions, both normal and pathological, including aging, memory, and neurodegenerative diseases. In this study, we examined whether Gadd45A deletion triggers pathways associated with neurodegenerative diseases including Alzheimer's disease (AD). MethodsUtilizing transcriptome data from AD-associated hippocampus samples, we identified Gadd45A as a pivotal regulator of autophagy. Comprehensive analyses, including Gene Ontology enrichment and protein-protein interaction network assessments, highlighted Cdkn1A as a significant downstream target of Gadd45A. Experimental validation confirmed Gadd45A's role in modulating Cdkn1A expression and autophagy levels in hippocampal cells. We also examined the effects of autophagy on hippocampal functions and proinflammatory cytokine secretion. Additionally, a murine model was employed to validate the importance of Gadd45A in neuroinflammation and AD pathology. ResultsOur study identified 20 autophagy regulatory factors associated with AD, with Gadd45A emerging as a critical regulator. Experimental findings demonstrated that Gadd45A influences hippocampal cell fate by reducing Cdkn1A expression and suppressing autophagic activity. Comparisons between wild-type (WT) and Gadd45A knockout (Gadd45A−/−) mice revealed that Gadd45A−/− mice exhibited significant cognitive impairments, including deficits in working and spatial memory, increased Tau hyperphosphorylation, and elevated levels of kinases involved in Tau phosphorylation in the hippocampus. Additionally, Gadd45A−/− mice showed significant increases in pro-inflammatory cytokines and decreases autophagy markers in the brain. Neurotrophin levels and dendritic spine length were also reduced in Gadd45A−/− mice, likely contributing to the observed cognitive deficits. ConclusionsThese findings support the direct involvement of the Gadd45A gene in AD pathogenesis, and enhancing the expression of Gadd45A may represent a promising therapeutic strategy for the treatment of AD.

Harmine inhibits pulmonary fibrosis through regulating DNA damage repair-related genes and activation of TP53-Gadd45α pathway

BackgroundHarmine has many pharmacological activities and has been found to significantly inhibit the fibrosis of keloid fibroblasts. DNA damage repair (DDR) is essential to prevent fibrosis. This study aimed to investigate the effects of harmine on pulmonary fibrosis and its underlying mechanisms. MethodsBleomycin and TGF-β1 were used to construct pulmonary fibrosis models in vivo and in vitro, then treated with harmine to explore harmine’s effects in treating experimental pulmonary fibrosis and its related mechanisms. Then, RNA sequencing was applied to investigate further the crucial DDR-related genes and drug targets of harmine against pulmonary fibrosis. Finally, the expression levels of DDR-related genes were verified by real-time quantitative PCR (RT-qPCR) and western blot. ResultsOur in vivo experiments showed that harmine treatment could improve weight loss and lung function and reduce tissue fibrosis in mice with pulmonary fibrosis. The results confirmed that harmine could inhibit the viability and migration of TGF-β1-induced MRC-5 cells, induce their apoptosis, and suppress the F-actin expression, suggesting that harmine could suppress the phenotypic transition from lung fibroblasts to lung myoblasts. In addition, RNA sequencing identified 1692 differential expressed genes (DEGs), and 10 DDR-related genes were screened as critical DDR-related genes. RT-qPCR and western blotting showed that harmine could down-regulate the expression of CHEK1, ERCC1, ERCC4, POLD1, RAD51, RPA1, TOP1, and TP53, while up-regulate FEN1, H2AX and GADD45α expression. ConclusionsHarmine may inhibit pulmonary fibrosis by regulating DDR-related genes and activating the TP53-Gadd45α pathway.

Silencing of the DNA damage repair regulator PPP1R15A sensitizes acute myeloid leukemia cells to chemotherapy

Acute Myeloid Leukemia (AML) is a life-threatening disease whose induction treatment consists of combination chemotherapy with Idarubicin and Cytarabine for fit patients. Treatment failures are frequent, urging the need for novel treatments for this disease. The DNA Damage Response Mechanism (DDR) comprises numerous molecules and pathways intended to arrest the cell cycle until DNA damage is repaired or else drive the cell to apoptosis. AML-derived cell lines after treatment with Idarubicin and Cytarabine were used for studying the expression profile of 84 DDR genes, through PCR arrays. Utilizing de novo AML patient and control samples we studied the expression of PPP1R15A, CDKN1A, GADD45A, GADD45G, and EXO1. Next, we performed PPP1R15A silencing in AML cell lines in two separate experiments using siRNA and CRISPR-cas9, respectively. Our findings highlight that DDR regulators demonstrate increased expression in patients with high cytogenetic risk possibly reflecting increased genotoxic stress. Especially, PPP1R15A is mainly involved in the recovery of the cells from stress and it was the only DDR gene upregulated in AML patients. The PPP1R15A silencing resulted in decreased viability of Idarubicin and Cytarabine-treated cell lines, in contrast to untreated cells. These findings shed light on new strategies to enhance chemotherapy efficacy and demonstrate that PPP1R15A is an important DDR regulator in AML and its downregulation might be a safe and effective way to increase sensitivity to chemotherapy in this disease.

#245 Deficiency of GADD45α expression mediated tubulointerstitial injury in diabetic nephropathy

Abstract Background and Aims The tubulointerstitial injury plays crucial roles in the development of diabetic nephropathy (DN). Recently, some studies have reported that disorder of mitochondrial fatty acid β-oxidation in proximal tubules is involved in tubulointerstitial injury of DN. The growth arrest and DNA damage-inducible gene 45 (GADD45) family proteins, especially, GADD45α, plays a crucial role in various cellular processes, such as mitochondrial biogenesis and lipid metabolism. Recent studies have demonstrated that GADD45α facilitates gene activation by inducing DNA demethylation. Therefore, this study aimed to investigate the role of GADD45α in tubulointerstitial injury of DN and its underlying mechanisms. Methods Bioinformatics and machine learning techniques were employed to identify differentially expressed genes between healthy individuals and DN patients. Experiments were conducted by using high glucose-treated HK-2 cells and streptozotocin (STZ)-induced mice. Lentivirus carrying the GADD45α gene was used to induce GADD45α overexpression in HK-2 cells. Adeno-Associated Virus vectors carrying LoxP-flanked GADD45α were intravenously injected into γGT-Cre transgenic mice expressing Cre recombinase in renal proximal tubular cells, specifically leading to GADD45α overexpression in proximal tubules. Results Through bioinformatics and machine learning techniques, GADD45α was identified and found to exhibit a strong association with tubulointerstitial injury in DN. Further analysis revealed that the expression of GADD45α was decreased in the kidneys of DN patients, diabetic mice, and high glucose-treated HK-2 cells. Notably, GADD45α overexpression ameliorated kidney damage and mitochondrial injury, leading to improved fatty acid β-oxidation, restored ATP production, and reduced ROS production. Transcriptomics analyses further demonstrated that GADD45α overexpression enhanced the expression of genes related to mitochondrial biogenesis, dynamics, and electron transport chain, with six transmembrane epithelial antigen of prostate 4 (STEAP4) being a key protein in this process. Knocking down STEAP4 using siRNA in HK-2 cells exacerbated the damage induced by high glucose. In addition, our further results indicated that high glucose increased methylation of the STEAP4 promoter, while GADD45α overexpression decreased methylation and increased STEAP4 expression. Conclusions Deficiency of GADD45α expression mediated tubulointerstitial injury in DN, which was mainly through the decreased STEAP4 expression by demethylating CpG motifs in the STEAP4 promoter region, thereby resulting in reduced fatty acid oxidation, energy synthesis, and increased ROS production, and finally accelerated tubular injuries. These findings suggested that targeting the GADD45α-STEAP4 pathway could be a potential therapeutic strategy for DN.

Evolution of a novel adrenal cell type that promotes parental care.

Cell types with specialized functions fundamentally regulate animal behaviour, and yet the genetic mechanisms that underlie the emergence of novel cell types and their consequences for behaviour are not well understood1. Here we show that the monogamous oldfield mouse (Peromyscus polionotus) has recently evolved a novel cell type in the adrenal gland that expresses the enzyme AKR1C18, which converts progesterone into 20α-hydroxyprogesterone. We then demonstrate that 20α-hydroxyprogesterone is more abundant in oldfield mice, where it induces monogamous-typical parental behaviours, than in the closely related promiscuous deer mice (Peromyscus maniculatus). Using quantitative trait locus mapping in a cross between these species, we ultimately find interspecific genetic variation that drives expression of the nuclear protein GADD45A and the glycoprotein tenascin N, which contribute to the emergence and function of this cell type in oldfield mice. Our results provide an example by which the recent evolution of a new cell type in a gland outside the brain contributes to the evolution of social behaviour.

Exploring CDKN1A Upregulation Mechanisms: Insights into Cell Cycle Arrest Induced by NC2603 Curcumin Analog in MCF-7 Breast Cancer Cells.

Breast cancer stands out as one of the most prevalent malignancies worldwide, necessitating a nuanced understanding of its molecular underpinnings for effective treatment. Hormone receptors in breast cancer cells substantially influence treatment strategies, dictating therapeutic approaches in clinical settings, serving as a guide for drug development, and aiming to enhance treatment specificity and efficacy. Natural compounds, such as curcumin, offer a diverse array of chemical structures with promising therapeutic potential. Despite curcumin's benefits, challenges like poor solubility and rapid metabolism have spurred the exploration of analogs. Here, we evaluated the efficacy of the curcumin analog NC2603 to induce cell cycle arrest in MCF-7 breast cancer cells and explored its molecular mechanisms. Our findings reveal potent inhibition of cell viability (IC50 = 5.6 μM) and greater specificity than doxorubicin toward MCF-7 vs. non-cancer HaCaT cells. Transcriptome analysis identified 12,055 modulated genes, most notably upregulation of GADD45A and downregulation of ESR1, implicating CDKN1A-mediated regulation of proliferation and cell cycle genes. We hypothesize that the curcumin analog by inducing GADD45A expression and repressing ESR1, triggers the expression of CDKN1A, which in turn downregulates the expression of many important genes of proliferation and the cell cycle. These insights advance our understanding of curcumin analogs' therapeutic potential, highlighting not just their role in treatment, but also the molecular pathways involved in their activity toward breast cancer cells.

Activation of the MEK/ERK Pathway Mediates the Inhibitory Effects of Silvestrol on Nasopharyngeal Carcinoma Cells via RAP1A, HK2, and GADD45A.

Nasopharyngeal carcinoma (NPC) is a malignant tumor associated with Epstein-Barr virus (EBV) infection. Chemoradiotherapy is the mainstream treatment for locally advanced NPC, and chemotherapeutic drugs are an indispensable part of NPC treatment. However, the toxic side-effects of chemotherapy drugs limit their therapeutic value, and new chemotherapy drugs are urgently needed for NPC. Silvestrol, an emerging natural plant anticancer molecule, has shown promising antitumor activity in breast cancer, melanoma, liver cancer, and other tumor types by promoting apoptosis in cancer cells to a greater extent than in normal cells. However, the effects of silvestrol on NPC and its possible molecular mechanisms have yet to be fully explored. Cell counting kit-8 (CCK-8), cell scratch, flow cytometry, 5-ethynyl-2'-deoxyuridine (EdU), and Western blot (WB) assays were used to evaluate the effects of silvestrol on the cell viability, cell cycle, apoptosis, and migration of NPC cells. RNA sequencing (RNA-Seq) was used to study the effect of extracellular signal-regulated kinase (ERK) inhibitors on the cell transcriptome, and immunohistochemistry (IHC) to assess protein expression levels in patient specimens. Silvestrol inhibited cell migration and DNA replication of NPC cells, while promoting the expression of cleaved caspase-3, apoptosis, and cell cycle arrest. Furthermore, silvestrol altered the level of ERK phosphorylation. The ERK-targeted inhibitor LY3214996 attenuated silvestrol-mediated inhibition of NPC cell proliferation but not migration. Analysis of RNA-Seq data and WB were used to identify and validate the downstream regulatory targets of silvestrol. Expression of GADD45A, RAP1A, and hexokinase-II (HK2) proteins was inhibited by silvestrol and LY3214996. Finally, IHC revealed that GADD45A, RAP1A, and HK2 protein expression was more abundant in cancer tissues than in non-tumor tissues. Silvestrol inhibits the proliferation of NPC cells by targeting ERK phosphorylation. However, the inhibition of NPC cell migration by silvestrol was independent of the Raf-MEK-ERK pathway. RAP1A, HK2, and GADD45A may be potential targets for the action of silvestrol.

Analysis and experimental validation of IL-17 pathway and key genes as central roles associated with inflammation in hepatic ischemia-reperfusion injury.

Hepatic ischemia-reperfusion injury (HIRI) elicits an immune-inflammatory response that may result in hepatocyte necrosis and apoptosis, ultimately culminating in postoperative hepatic dysfunction and hepatic failure. The precise mechanisms governing the pathophysiology of HIRI remain incompletely understood, necessitating further investigation into key molecules and pathways implicated in disease progression to guide drug discovery and potential therapeutic interventions. Gene microarray data was downloaded from the GEO expression profile database. Integrated bioinformatic analyses were performed to identify HIRI signature genes, which were subsequently validated for expression levels and diagnostic efficacy. Finally, the gene expression was verified in an experimental HIRI model and the effect of anti-IL17A antibody intervention in three time points (including pre-ischemic, post-ischemic, and at 1h of reperfusion) on HIRI and the expression of these genes was investigated. Bioinformatic analyses of the screened characterized genes revealed that inflammation, immune response, and cell death modulation were significantly associated with HIRI pathophysiology. CCL2, BTG2, GADD45A, FOS, CXCL10, TNFRSF12A, and IL-17 pathway were identified as key components involved in the HIRI. Serum and liver IL-17A expression were significantly upregulated during the initial phase of HIRI. Pretreatment with anti-IL-17A antibody effectively alleviated the damage of liver tissue, suppressed inflammatory factors, and serum transaminase levels, and downregulated the mRNA expression of CCL2, GADD45A, FOS, CXCL10, and TNFRSF12A. Injection of anti-IL17A antibody after ischemia and at 1h of reperfusion failed to demonstrate anti-inflammatory and attenuating HIRI benefits relative to earlier intervention. Our study reveals that the IL-17 pathway and related genes may be involved in the proinflammatory mechanism of HIRI, which may provide a new perspective and theoretical basis for the prevention and treatment of HIRI.

Deletion of Gadd45a Expression in Mice Leads to Cognitive and Synaptic Impairment Associated with Alzheimer's Disease Hallmarks.

Gadd45 genes have been implicated in survival mechanisms, including apoptosis, autophagy, cell cycle arrest, and DNA repair, which are processes related to aging and life span. Here, we analyzed if the deletion of Gadd45a activates pathways involved in neurodegenerative disorders such as Alzheimer's Disease (AD). This study used wild-type (WT) and Gadd45a knockout (Gadd45a-/-) mice to evaluate AD progression. Behavioral tests showed that Gadd45a-/- mice presented lower working and spatial memory, pointing out an apparent cognitive impairment compared with WT animals, accompanied by an increase in Tau hyperphosphorylation and the levels of kinases involved in its phosphorylation in the hippocampus. Moreover, Gadd45a-/- animals significantly increased the brain's pro-inflammatory cytokines and modified autophagy markers. Notably, neurotrophins and the dendritic spine length of the neurons were reduced in Gadd45a-/- mice, which could contribute to the cognitive alterations observed in these animals. Overall, these findings demonstrate that the lack of the Gadd45a gene activates several pathways that exacerbate AD pathology, suggesting that promoting this protein's expression or function might be a promising therapeutic strategy to slow down AD progression.

The effect of vine tea (Ampelopsis grossedentata) extract on fatigue alleviation via improving muscle mass

Ethnopharmacological relevanceVine Tea (VT, Ampelopsis grossedentata), boasts a venerable tradition in China, with a recorded consumption history exceeding 1200 years. Predominantly utilized by ethnic groups in southwest China, this herbal tea is celebrated for its multifaceted therapeutic attributes. Traditionally, VT has been employed to alleviate heat and remove toxins, exhibit anti-inflammatory properties, soothe sore throats, lower blood pressure, and fortify bones and muscles. In the realm of functional foods derived from plant resources, VT has garnered attention for its potential in crafting anti-fatigue beverages or foods, attributed to its promising efficacy and minimal side effects. Currently, in accordance with the Food Safety Standards set forth by the Monitoring and Evaluation Department of the National Health and Family Planning Commission in China, VT serves as a raw material in various beverages. Aim of the studyVT has an anti-fatigue or similar effect in folk. However, the underlying molecular mechanisms contributing to VT's anti-fatigue effects remain elusive. This study endeavors to investigate the influence of Vine Tea Aqueous Extract (VTE) on fatigue mitigation and to elucidate its operative mechanisms, with the objective of developing VTE as a functional beverage. Materials and methodsThe preparation of VTE involved heat extraction and freeze-drying processes, followed by the identification of its metabolites using UPLC-QTOF-MS to ascertain the chemical composition of VTE. A fatigue model was established using a forced swimming test in mice. Potential molecular targets were identified through network pharmacology, transcriptome analysis, and molecular docking. Furthermore, RT-PCR and Western blot techniques were employed to assess mRNA and protein expressions related to the AMPK and FoxO pathways. ResultsVTE significantly prolonged the duration of swimming time in an exhaustive swimming test in a dose-dependent manner, while simultaneously reducing the concentrations of blood lactic acid (LA), lactate dehydrogenase (LDH), serum urea nitrogen (SUN), and creatine kinase (CK). Notably, the performance of the high-dose VTE group surpassed that of the well-recognized ginsenoside. VTE demonstrated a regulatory effect akin to ginsenoside on the AMPK energy metabolism pathway and induced downregulation in the expression of Gadd45α, Cdkn1a, FOXO1, and Fbxo32 genes, suggesting an enhancement in skeletal muscle mass. These findings indicate that VTE can improve energy metabolism and muscle mass concurrently. ConclusionsVTE exhibits significant anti-fatigue effects, and its mechanism is intricately linked to the modulation of the AMPK and FoxO pathways. Crucially, no caffeine or other addictive substances with known side effects were detected in VTE. Consequently, vine tea shows substantial promise as a natural resource for the development of anti-fatigue beverages within the food industry.

Identification of potential crucial genes and therapeutic targets for epilepsy

BackgroundEpilepsy, a central neurological disorder, has a complex genetic architecture. There is some evidence suggesting that genetic factors play a role in both the occurrence of epilepsy and its treatment. However, the genetic determinants of epilepsy are largely unknown. This study aimed to identify potential therapeutic targets for epilepsy.MethodsDifferentially expressed genes (DEGs) were extracted from the expression profiles of GSE44031 and GSE1834. Gene co-expression analysis was used to confirm the regulatory relationship between newly discovered epilepsy candidate genes and known epilepsy genes. Expression quantitative trait loci analysis was conducted to determine if epilepsy risk single-nucleotide polymorphisms regulate DEGs’ expression in human brain tissue. Finally, protein–protein interaction analysis and drug–gene interaction analysis were performed to assess the role of DEGs in epilepsy treatment.ResultsThe study found that the protein tyrosine phosphatase receptor-type O gene (PTPRO) and the growth arrest and DNA damage inducible alpha gene (GADD45A) were significantly upregulated in epileptic rats compared to controls in both datasets. Gene co-expression analysis revealed that PTPRO was co-expressed with RBP4, NDN, PAK3, FOXG1, IDS, and IDS, and GADD45A was co-expressed with LRRK2 in human brain tissue. Expression quantitative trait loci analysis suggested that epilepsy risk single-nucleotide polymorphisms could be responsible for the altered PTPRO and GADD45A expression in human brain tissue. Moreover, the protein encoded by GADD45A had a direct interaction with approved antiepileptic drug targets, and GADD45A interacts with genistein and cisplatin.ConclusionsThe results of this study highlight PTPRO and GADD45A as potential genes for the diagnosis and treatment of epilepsy.

GADD45A is a mediator of mitochondrial loss, atrophy, and weakness in skeletal muscle.

Aging and many illnesses and injuries impair skeletal muscle mass and function, but the molecular mechanisms are not well understood. To better understand the mechanisms, we generated and studied transgenic mice with skeletal muscle-specific expression of growth arrest and DNA damage inducible α (GADD45A), a signaling protein whose expression in skeletal muscle rises during aging and a wide range of illnesses and injuries. We found that GADD45A induced several cellular changes that are characteristic of skeletal muscle atrophy, including a reduction in skeletal muscle mitochondria and oxidative capacity, selective atrophy of glycolytic muscle fibers, and paradoxical expression of oxidative myosin heavy chains despite mitochondrial loss. These cellular changes were at least partly mediated by MAP kinase kinase kinase 4, a protein kinase that is directly activated by GADD45A. By inducing these changes, GADD45A decreased the mass of muscles that are enriched in glycolytic fibers, and it impaired strength, specific force, and endurance exercise capacity. Furthermore, as predicted by data from mouse models, we found that GADD45A expression in skeletal muscle was associated with muscle weakness in humans. Collectively, these findings identify GADD45A as a mediator of mitochondrial loss, atrophy, and weakness in mouse skeletal muscle and a potential target for muscle weakness in humans.

GADD45A regulates subcutaneous fat deposition and lipid metabolism by interacting with Stat1

BackgroundObesity, characterized by excessive white adipose tissue expansion, is associated with several metabolic complications. Identifying new adipogenesis regulators may lead to effective therapies for obesity-induced metabolic disorders.ResultsHere, we identified the growth arrest and DNA damage-inducible A (GADD45A), a stress-inducible histone-folding protein, as a novel regulator of subcutaneous adipose metabolism. We found that GADD45A expression was positively correlated with subcutaneous fat deposition and obesity in humans and fatty animals. In vitro, the gain or loss function of GADD45A promoted or inhibited subcutaneous adipogenic differentiation and lipid accumulation, respectively. Using a Gadd45a-/- mouse model, we showed that compared to wild-type (WT) mice, knockout (KO) mice exhibited subcutaneous fat browning and resistance to high-fat diet (HFD)-induced obesity. GADD45A deletion also upregulated the expression of mitochondria-related genes. Importantly, we further revealed that the interaction of GADD45A with Stat1 prevented phosphorylation of Stat1, resulting in the impaired expression of Lkb1, thereby regulating subcutaneous adipogenesis and lipid metabolism.ConclusionsOverall, our results reveal the critical regulatory roles of GADD45A in subcutaneous fat deposition and lipid metabolism. We demonstrate that GADD45A deficiency induces the inguinal white adipose tissue (iWAT) browning and protects mice against HFD-induced obesity. Our findings provide new potential targets for combating obesity-related metabolic diseases and improving human health.

Aberrant expression of CKS2 induced by ELK1 contributes to malignant progression of pancreatic cancer.

Cyclin-dependent kinase subunit 2 (CKS2) has been reported to promote various malignancies. This study investigated the functional role of CKS2 in pancreatic cancer (PC). An analysis of abnormally expressed genes and their prognostic value for PC was performed by using the Gene Expression Profiling Interactive Analysis (GEPIA) database and performing immunohistochemical staining on 64 samples of tumor tissue. CCK-8 assays, EdU staining, colony formation assays, flow cytometry, and a xenograft tumor model were used to analyze the biological function of CKS2 in PC. Our results revealed that CKS2 was expressed at significantly higher levels in PC tissues than in adjacent normal tissues, and a high level of CKS2 expression was associated with a poor prognosis for patients with PC. Moreover, functional assays revealed that CKS2 knockdown suppressed cell proliferation, induced cell cycle S phase, G2/M phase arrest, and apoptosis in vitro, and also reduced tumor growth in vivo. In addition, CKS2 knockdown increased the levels of Bax, caspase-3, P53, P21, and GADD45α expression, but decreased Bcl-2, Cyclin B1, CDK1, Cyclin A, and Cdc25C expression. CKS2 overexpression produced the opposite effects of CKS2 knockdown. Furthermore, we found that ELK1 protein regulated transcription of the CKS2 gene. In conclusion, our findings suggest that CKS2 expression is regulated by ELK1, which could possibly serve as prognostic indicator and therapeutic target for PC.

GADD45A and GADD45B as Novel Biomarkers Associated with Chromatin Regulators in Renal Ischemia-Reperfusion Injury.

Chromatin regulators (CRs) are essential upstream regulatory factors of epigenetic modification. The role of CRs in the pathogenesis of renal ischemia-reperfusion injury (IRI) remains unclear. We analyzed a bioinformatic analysis on the differentially expressed chromatin regulator genes in renal IRI patients using data from public domains. The hub CRs identified were used to develop a risk prediction model for renal IRI, and their expressions were also validated using Western blot, qRT-PCR, and immunohistochemistry in a murine renal IRI model. We also examined the relationships between hub CRs and infiltrating immune cells in renal IRI and used network analysis to explore drugs that target hub CRs and their relevant downstream microRNAs. The results of machine learning methods showed that five genes (DUSP1, GADD45A, GADD45B, GADD45G, HSPA1A) were upregulated in renal IRI, with key roles in the cell cycle, p38 MAPK signaling pathway, p53 signaling pathway, FoxO signaling pathway, and NF-κB signaling pathway. Two genes from the network, GADD45A and GADD45B (growth arrest and DNA damage-inducible protein 45 alpha and beta), were chosen for the renal IRI risk prediction model. They all showed good performance in the testing and validation cohorts. Mice with renal IRI showed significantly upregulated GADD45A and GADD45B expression within kidneys compared to sham-operated mice. GADD45A and GADD45B showed correlations with plasmacytoid dendritic cells (pDCs) in infiltrating immune cell analysis and enrichment in the MAPK pathway based on the weighted gene co-expression network analysis (WGCNA) method. Candidate drugs that target GADD45A and GADD45B include beta-escin, sertraline, primaquine, pimozide, and azacyclonol. The dysregulation of GADD45A and GADD45B is related to renal IRI and the infiltration of pDCs, and drugs that target GADD45A and GADD45B may have therapeutic potential for renal IRI.

The DNA damage response to radiological imaging: from ROS and γH2AX foci induction to gene expression responses in vivo

Candidate ionising radiation exposure biomarkers must be validated in humans exposed in vivo. Blood from patients undergoing positron emission tomography–computed tomography scan (PET-CT) and skeletal scintigraphy (scintigraphy) was drawn before (0 h) and after (2 h) the procedure for correlation analyses of the response of selected biomarkers with radiation dose and other available patient information. FDXR, CDKN1A, BBC3, GADD45A, XPC, and MDM2 expression was determined by qRT-PCR, DNA damage (γH2AX) by flow cytometry, and reactive oxygen species (ROS) levels by flow cytometry using the 2′, 7′—dichlorofluorescein diacetate test in peripheral blood mononuclear cells (PBMC). For ROS experiments, 0- and 2-h samples were additionally exposed to UVA to determine whether diagnostic irradiation conditioned the response to further oxidative insult. With some exceptions, radiological imaging induced weak γH2AX foci, ROS and gene expression fold changes, the latter with good coherence across genes within a patient. Diagnostic imaging did not influence oxidative stress in PBMC successively exposed to UVA. Correlation analyses with patient characteristics led to low correlation coefficient values. γH2AX fold change, which correlated positively with gene expression, presented a weak positive correlation with injected activity, indicating a radiation-induced subtle increase in DNA damage and subsequent activation of the DNA damage response pathway. The exposure discrimination potential of these biomarkers in the absence of control samples as frequently demanded in radiological emergencies, was assessed using raw data. These results suggest that the variability of the response in heterogeneous populations might complicate identifying individuals exposed to low radiation doses.

Nuclear complement C3b promotes paclitaxel resistance by assembling the SIN3A/HDAC1/2 complex in non-small cell lung cancer

In addition to the classical role as a serum effector system of innate immunity, accumulating evidence suggests that intracellular complement components have indispensable functions in immune defense, T cell homeostasis, and tumor cell proliferation and metastasis. Here, we revealed that complement component 3 (C3) is remarkably upregulated in paclitaxel (PTX)-resistant non-small cell lung cancer (NSCLC) cells and that knockdown of C3 promoted PTX-induced cell apoptosis, sensitizing resistant cells to PTX therapy. Ectopic C3 decreased PTX-induced apoptosis and induced resistance to PTX treatment in original NSCLC cells. Interestingly, C3b, the activated fragment of C3, was found to translocate into the nucleus and physically associate with the HDAC1/2-containing SIN3A complex to repress the expression of GADD45A, which plays an important role in cell growth inhibition and apoptosis induction. Importantly, C3 downregulated GADD45A by enhancing the binding of the SIN3A complex with the promoter of GADD45A, thus decreasing the H3Ac level to compress chromatin around the GADD45A locus. Subsequently, ectopic GADD45A promoted PTX-induced cell apoptosis, sensitizing resistant cells to PTX therapy, and insufficiency of GADD45A in original cancer cells induced resistance to PTX treatment. These findings identify a previously unknown nucleus location and oncogenic property for C3 in chemotherapy and provide a potential therapeutic opportunity to overcome PTX resistance.