Ezer S, Ronin N, Yanovsky-Dagan S, Rotem-Bamberger S, Halstuk O, Wexler Y, Ben-Moshe Z, Plaschkes I, Benyamini H, Saada A, Inbal A, Harel T. Transcriptome analysis of atad3-null zebrafish embryos elucidates possible disease mechanisms [Internet]. Orphanet J Rare DisOrphanet journal of rare diseases 2025;20(1):181.Available from: https://pubmed.ncbi.nlm.nih.gov/40234890/ PubMedBACKGROUND: ATAD3A, a nuclear gene encoding the ATAD3A protein, has diverse roles in mitochondrial processes, encompassing mitochondrial dynamics, mitochondrial DNA maintenance, metabolic pathways and inter-organellar interactions. Pathogenic variants in this gene cause neurological diseases in humans with recognizable genotype-phenotype correlations. Yet, gaps in knowledge remain regarding the underlying pathogenesis. METHODS: To further investigate the gene function and its implication in health and disease, we utilized CRISPR/Cas9 genome editing to generate a knockout model of the zebrafish ortholog gene, atad3. We characterized the phenotype of the null model, performed mitochondrial and functional tests, and compared the transcriptome of null embryos to their healthy siblings. RESULTS: Analysis of atad3-null zebrafish embryos revealed microcephaly, small eyes, pericardial edema and musculature thinning, closely mirroring the human rare disease phenotype. Larvae exhibited delayed hatching and embryonic lethality by 13 days post-fertilization (dpf). Locomotor activity, ATP content, mitochondrial content, and mitochondrial activity were all reduced in the mutant embryos. Transcriptome analysis at 3 dpf via RNA-sequencing indicated decline in most mitochondrial pathways, accompanied by a global upregulation of cytosolic tRNA synthetases, presumably secondary to mitochondrial stress and possibly endoplasmic reticulum (ER)-stress. Differential expression of select genes was corroborated in fibroblasts from an affected individual. CONCLUSIONS: The atad3-null zebrafish model emerges as a reliable representation of human ATAD3A-associated disorders, with similarities in differentially expressed pathways and processes. Furthermore, our study underscores mitochondrial dysfunction as the primary underlying pathogenic mechanism in ATAD3A-associated disorders and identifies potential readouts for therapeutic studies.
Zaffran I, Zoabi Y, Gaur P, Alekberli FRahimli, Tiligada E, Yutkin V, Levi-Schaffer F. Eosinophils but not mast cells exert anti-tumorigenic activity, without being predictive markers of the long-term response to Bacillus Calmette-Guérin (BCG) therapy in patients with bladder carcinoma [Internet]. Inflamm ResInflammation research : official journal of the European Histamine Research Society .. [et al.] 2025;74(1):68.Available from: https://pubmed.ncbi.nlm.nih.gov/40272538/ PubMedBACKGROUND: Bacillus Calmette-Guerin (BCG) therapy is an established immunotherapy for non-muscle invasive bladder cancer (NMIBC); however, the response variability of patients remains a challenge, necessitating insight into immune cell function. Previous studies established that a preexisting Th2 immune microenvironment correlates with a positive BCG therapy outcome. Therefore, in this study, we explored the role of mast cells (MCs) and eosinophils in bladder cancer as a potential predicting tool for BCG immunotherapy response. METHODS: We investigated the effect of MCs and eosinophils on bladder cancer cell viability together with their chemotactic migration towards cancer cells in vitro. The effect of BCG on these immune cells was also evaluated. Moreover, we performed an orthotopic model of bladder cancer in MC- and eosinophil-deficient mice. Finally, to evaluate whether these immune cells predict the therapy response, 26 patient biopsies pre-BCG treatment were analyzed for MC and eosinophil numbers in the tissue and sequenced for gene expression. RESULTS: Eosinophils, but not MCs, reduced bladder cancer cell viability in vitro and inhibited tumor growth in vivo. However, addition of BCG did not increase these effects in vitro. Patient biopsy analysis and mRNA sequencing showed that neither cell type predicted long-term therapy responsiveness. Gene expression analysis suggested that extracellular matrix and epithelial-to-mesenchymal transition factors could influence BCG therapy outcomes. CONCLUSION: Even though eosinophils exhibit anti-tumorigenic effects in bladder cancer, neither MCs nor eosinophils were predictive of the long-term BCG therapy response. However, our findings implicate that matrix-related factors may modulate BCG therapy responses.
Heng CKMatthew, Darlyuk-Saadon I, Liao W, Mohanam MP, Gan PXL, Gilad N, M Y Chan CC, Plaschkes I, Wong WSFred, Engelberg D. A combination of alveolar type 2-specific p38α activation with a high-fat diet increases inflammatory markers in mouse lungs [Internet]. J Biol ChemThe Journal of biological chemistry 2025;301(4):108425.Available from: https://pubmed.ncbi.nlm.nih.gov/40118456/ PubMedChronic respiratory diseases such as asthma and chronic obstructive pulmonary disease afflict millions of individuals globally and are significant sources of disease mortality. While the molecular mechanisms underlying such diseases are unclear, environmental and social factors, such as cigarette smoke and obesity, increase the risk of disease development. Yet, not all smokers or obese individuals will develop chronic respiratory diseases. The mitogen-activated protein kinase p38α is abnormally active in such maladies, but its contribution, if any, to disease etiology is unknown. To assess whether p38α activation per se in the lung could impose disease symptoms, we generated a transgenic mouse model allowing controllable expression of an intrinsically active variant, p38α(D176A+F327S), specifically in lung alveolar type 2 pneumocytes. Sustained expression of p38α(D176A+F327S) did not appear to induce obvious pathological outcomes or to exacerbate inflammatory outcomes in mice challenged with common respiratory disease triggers. However, mice expressing p38α(D176A+F327S) in alveolar type 2 cells and fed with a high-fat diet exhibited increased numbers of airway eosinophils and lymphocytes, upregulated levels of proinflammatory cytokines and chemokines including interleukin-1β and eotaxin, as well as a reduction in levels of leptin and adiponectin within the lung. Neither high-fat diet nor p38α(D176A+F327S) alone induced such outcomes. Perhaps in obese individuals with associated respiratory diseases, elevated p38α activity which happens to occur is the factor that promotes their development.
Raiter A, Barhum Y, Lipovetsky J, Menachem C, Elgavish S, Ruppo S, Birger Y, Izraeli S, Steinberg-Shemer O, Yerushalmi R. Galectin-3 secreted by triple-negative breast cancer cells regulates T cell function [Internet]. NeoplasiaNeoplasia (New York, N.Y.) 2024;60:101117.Available from: https://pubmed.ncbi.nlm.nih.gov/39729650/ PubMedTriple-negative breast cancer (TNBC) is an aggressive subtype that accounts for 10-15 % of breast cancer. Current treatment of high-risk early-stage TNBC includes neoadjuvant chemo-immune therapy. However, the substantial variation in immune response prompts an urgent need for new immune-targeting agents. This requires a comprehensive understanding of TNBC's tumor microenvironment. We recently demonstrated that Galectin-3 (Gal-3) binding protein/Gal-3 complex secreted by TNBC cells induces immunosuppression, through inhibiting CD45 signaling in T cells. Here, we further investigated the interaction between secreted Gal-3 and T cells in TNBC. Using CRISPR/Cas9 gene editing of the TNBC MDA-MB-231 cell-line, we obtained Gal-3 negative((neg)) clones. We studied these in an in-vitro model, co-cultured with peripheral blood mononuclear cells (PBMC) to imitate immune-tumor interaction, and in an in-vivo model, when implanted in mice. Gal-3(neg) tumors in mice had decelerated tumor growth after PBMC inoculation. In contrast, the Gal-3 positive((pos)) tumors continued growing despite PBMC inoculation, and tumor T regulatory cell (CD4/FoxP3+) infiltration increased. RNA sequencing of T cells from women with TNBC with elevated plasma levels of Gal-3 revealed significantly lower expression of oxidative phosphorylation genes than in T cells from healthy women. Similarly, in our in-vitro model, the decreased expression of oxidative phosphorylation genes and mitochondrial dysfunction resulted in a significant increase in CD8 intracellular reactive oxygen species. Consequently, T exhausted cells (CD8/PD1/Tim3/Lag3+) significantly increased in PBMC co-cultured with Gal-3(pos) TNBCs. To conclude, we revealed a novel TNBC-related Gal-3 suppressor mechanism that involved upregulation of CD4 T regulatory and of CD8 T exhausted cells.
Dayan J, Uni Z. Gene ontology defines pre-post- hatch energy dynamics in the complexus muscle of broiler chickens [Internet]. BMC GenomicsBMC genomics 2024;25(1):1180.Available from: https://pubmed.ncbi.nlm.nih.gov/39633257/ PubMedBACKGROUND: Chicken embryos emerge from their shell by the piercing movement of the hatching muscle. Although considered a key player during hatching, with activity that imposes a substantial metabolic demand, data are still limited. The study provides a bioenergetic and transcriptomic analyses during the pre-post-hatching period. METHODS: Weight and morphology alongside content determination of creatine and glycogen were analysed. Transcriptome identified differentially expressed genes and enriched biological processes associated with hatching muscle development, catabolism, and energy provision. Using gene set enrichment, we followed the dynamics of gene-sets involved in energy pathways of oxidative phosphorylation, protein catabolism, glycolysis/gluconeogenesis, and glycogen metabolism. RESULTS: Results show several significant findings: (A) Creatine plays a crucial role in the energy metabolism of the hatching muscle, with its concentration remaining stable while glycogen concentration is depleted at hatch and placement. (B) The hatching muscle has the capacity for de-novo creatine synthesis, as indicated by the expression of related genes (AGAT, GAMT). (C) Transcriptome provided insights into genes related to energy pathways under conditions of pre-hatch oxygen and post-hatch glucose limitations (oxidative phosphorylation: NDUF, MT-ND, SDH, UQCR, COX, MT-CO, ATP5, MT-ATP; glycolysis/gluconeogenesis: FBP,G6PC, PFKM; glycogen metabolism: PPP1, PYGL, GYG1). (D) The post-hatch upregulation of protein catabolic processes genes (PSMA, RNF, UBE, FBX), which align with the muscle's weight dynamics, indicates a functional shift from movement during hatching to lifting the head during feeding. CONCLUSIONS: There is a dynamic metabolic switch in the hatching muscle during embryo-to-hatchling transition. When glycogen concentration depletes, energy supply is maintained by creatine and its de-novo synthesis. Understanding the hatching muscle's energy dynamics is crucial, for reducing hatching failures in endangered avian species, and in domesticated chickens.
Makayes Y, Abergel E, Amleh A, Varshavsky DBinyamin, Fok R, Azria B, Ansari I, Bergman Y, Nechama M, Volovelsky O. Maternal Malnutrition in Mice Impairs Nephrogenesis by Disrupting DNA Methylation of Regulatory Regions [Internet]. Am J Physiol Renal Physiol 2024;Available from: https://pubmed.ncbi.nlm.nih.gov/39417827/ PubMed
Maternal caloric restriction during pregnancy significantly impacts kidney development, influencing susceptibility to chronic kidney disease in adulthood. This study explores DNA methylation changes in nephron progenitor cells resulting from caloric restriction and their implications for kidney health. Global DNA hypomethylation is observed in nephron progenitors from caloric-restricted embryos, with specific genomic regions displaying distinct methylation patterns, including hypomethylation and hypermethylation. Differentially methylated regions exhibit enhanced chromatin accessibility, indicating biological relevance. Hypomethylated regions are enriched for genes associated with developmental processes, reflecting changes in gene expression and highlighting their functional relevance in kidney development. The study also reveals that supplementing methionine, an essential amino acid, restores disrupted DNA methylation patterns, particularly in enhancer regions, emphasizing methionine's critical role in regulating nephron progenitor cell epigenetics and ensuring proper kidney development. The intricate relationship between maternal nutrition, dynamic DNA methylation, and kidney development is highlighted, emphasizing the enduring impact of early-life nutritional challenges on kidney function. This research elucidates epigenetic mechanisms as mediators for the lasting effects of maternal caloric restriction on kidney health. The study contributes valuable insights into the origins of chronic kidney diseases during early developmental stages, offering potential interventions to mitigate adverse outcomes.
Gilad N, Mohanam MPayini, Darlyuk-Saadon I, Heng CKMatthew, Plaschkes I, Benyamini H, Berezhnoy NV, Engelberg D. Asynchronous Pattern of MAPKs' Activity during Aging of Different Tissues and of Distinct Types of Skeletal Muscle. Int J Mol Sci 2024;25(3)
The MAPK p38α was proposed to be a prominent promoter of skeletal muscle aging. The skeletal muscle tissue is composed of various muscle types, and it is not known if p38α is associated with aging in all of them. It is also not known if p38α is associated with aging of other tissues. JNK and ERK were also proposed to be associated with aging of several tissues. Nevertheless, the pattern of p38α, JNK, and ERK activity during aging was not documented. Here, we documented the levels of phosphorylated/active p38α, Erk1/2, and JNKs in several organs as well as the soleus, tibialis anterior, quadriceps, gastrocnemius, and EDL muscles of 1-, 3-, 6-, 13-, 18-, and 24-month-old mice. We report that in most tissues and skeletal muscles, the MAPKs' activity does not change in the course of aging. In most tissues and muscles, p38α is in fact active at younger ages. The quadriceps and the lungs are exceptions, where p38α is significantly active only in mice 13 months old or older. Curiously, levels of active JNK and ERKs are also elevated in aged lungs and quadriceps. RNA-seq analysis of the quadriceps during aging revealed downregulation of proteins related to the extra-cellular matrix (ECM) and ERK signaling. A panel of mRNAs encoding cell cycle inhibitors and senescence-associated proteins, considered to be aging markers, was not found to be elevated. It seems that the pattern of MAPKs' activation in aging, as well as expression of known 'aging' components, are tissue- and muscle type-specific, supporting a notion that the process of aging is tissue- and even cell-specific.
Hutchings C, Nuriel Y, Lazar D, Kohl A, Muir E, Genin O, Cinnamon Y, Benyamini H, Nevo Y, Sela-Donenfeld D. Hindbrain boundaries as niches of neural progenitor and stem cells regulated by the extracellular matrix proteoglycan chondroitin sulphate. Development 2024;151(4)
The interplay between neural progenitors and stem cells (NPSCs), and their extracellular matrix (ECM) is a crucial regulatory mechanism that determines their behavior. Nonetheless, how the ECM dictates the state of NPSCs remains elusive. The hindbrain is valuable to examine this relationship, as cells in the ventricular surface of hindbrain boundaries (HBs), which arise between any two neighboring rhombomeres, express the NPSC marker Sox2, while being surrounded with the membrane-bound ECM molecule chondroitin sulphate proteoglycan (CSPG), in chick and mouse embryos. CSPG expression was used to isolate HB Sox2+ cells for RNA-sequencing, revealing their distinguished molecular properties as typical NPSCs, which express known and newly identified genes relating to stem cells, cancer, the matrisome and cell cycle. In contrast, the CSPG- non-HB cells, displayed clear neural-differentiation transcriptome. To address whether CSPG is significant for hindbrain development, its expression was manipulated in vivo and in vitro. CSPG manipulations shifted the stem versus differentiation state of HB cells, evident by their behavior and altered gene expression. These results provide further understanding of the uniqueness of hindbrain boundaries as repetitive pools of NPSCs in-between the rapidly growing rhombomeres, which rely on their microenvironment to maintain their undifferentiated state during development.
Mitrani-Rosenbaum S, Attali R, Argov Z. GNE myopathy: can homozygous asymptomatic subjects give a clue for the identification of protective factors?. Neuromuscul Disord 2023;33(10):762-768.
GNE myopathy is caused by bi allelic recessive mutations in the GNE gene. The largest identified cohort of GNE myopathy patients carries a homozygous mutation- M743T (the "Middle Eastern" mutation). More than 160 such patients in 67 families have been identified by us. Mean onset in this cohort is 30 years (range 17-48) with variable disease severity. However, we have identified two asymptomatic females, homozygous for M743T in two different families, both with affected siblings. The first showed no myopathy when examined at age 76 years. The second has no sign of disease at age 60 years. Since both agreed only for testing of blood, we performed exome and RNA sequencing of their blood and that of their affected siblings. Various filtering layers resulted in 2723 variant loci between symptomatic and asymptomatic individuals, representing 1364 genes. Among those, 39 genes are known to be involved in neuromuscular diseases, and only in two of them the variant is located in the proper exon coding region, resulting in a missense change. Surprisingly, only 27 genes were significantly differentially expressed between the asymptomatic and the GNE myopathy affected individuals, with three overexpressed genes overlapping between exome and RNA sequencing. Although unable to unravel robust candidate genes, mostly because of the very low number of asymptomatic individuals analyzed, and because of the tissue analyzed (blood and not muscle), this study resulted in relatively restricted potential candidate protective genes, emphasizing the power of using polarized phenotypes (completely asymptomatic vs clearly affected individuals) with the same genotype to unmask those genes which could be used as targets for disease course modifiers.
Ambastha V, Nevo Y, Matityhu I, Honys D, Leshem Y. Discovery of microRNAs in stigma exudates opens new research avenues in Horticulture. PNAS Nexus 2023;2(11):pgad332.
In many plant species, flower stigma secretions are important in early stages of sexual reproduction. Previous chemical analysis and proteomic characterization of these exudates provided insights into their biological function. Nevertheless, the presence of nucleic acids in the stigma exudates has not been previously reported. Here, we studied the stigma exudates of , , and and showed them to harbor extracellular RNAs of various sizes. RNA sequencing revealed, for the first time, the presence of known Rosaceae mature microRNAs (miRs), also abundant in the stigma source tissue. Predicted targets of the exudate miRs in the genome include genes involved in various biological processes. Several of these genes are pollen transcribed, suggesting possible involvement of exudate miRs in transcriptional regulation of the pollen. Moreover, extracellular miRs can potentially act across kingdoms and target genes of stigma interacting organisms/microorganisms, thus opening novel applicative avenues in Horticulture.
Fracchia A, Khare D, Da'na S, Or R, Buxboim A, Nachmias B, Barkatz C, Golan-Gerstl R, Tiwari S, Stepensky P, Nevo Y, Benyamini H, Elgavish S, Almogi-Hazan O, Avni B. Mesenchymal Stromal Cell-Derived Small Extracellular Vesicles Modulate Apoptosis, TNF Alpha and Interferon Gamma Response Gene mRNA Expression in T Lymphocytes. Int J Mol Sci 2023;24(18)
Recent studies have highlighted the therapeutic potential of small extracellular bodies derived from mesenchymal stem cells (MSC-sEVs) for various diseases, notably through their ability to alter T-cell differentiation and function. The current study aimed to explore immunomodulatory pathway alterations within T cells through mRNA sequencing of activated T cells cocultured with bone marrow-derived MSC-sEVs. mRNA profiling of activated human T cells cocultured with MSC-sEVs or vehicle control was performed using the QIAGEN Illumina sequencing platform. Pathway networks and biological functions of the differentially expressed genes were analyzed using Ingenuity pathway analysis (IPA) software, KEGG pathway, GSEA and STRING database. A total of 364 differentially expressed genes were identified in sEV-treated T cells. Canonical pathway analysis highlighted the RhoA signaling pathway. Cellular development, movement, growth and proliferation, cell-to-cell interaction and inflammatory response-related gene expression were altered. KEGG enrichment pathway analysis underscored the apoptosis pathway. GSEA identified enrichment in downregulated genes associated with TNF alpha and interferon gamma response, and upregulated genes related to apoptosis and migration of lymphocytes and T-cell differentiation gene sets. Our findings provide valuable insights into the mechanisms by which MSC-sEVs implement immunomodulatory effects on activated T cells. These findings may contribute to the development of MSC-sEV-based therapies.
Elsana H, Bruck-Haimson R, Zhu H, Siddiqui AAhmed, Zaretsky A, Cohen I, Boocholez H, Roitenberg N, Moll L, Plaschkes I, Naor D, Cohen E. A short peptide protects from age-onset proteotoxicity. Aging Cell 2023;:e14013.
Aberrant protein aggregation jeopardizes cellular functionality and underlies the development of a myriad of late-onset maladies including Alzheimer's disease (AD) and Huntington's disease (HD). Accordingly, molecules that mitigate the toxicity of hazardous protein aggregates are of great interest as potential future therapeutics. Here we asked whether a small peptide, composed of five amino acids (5MER peptide) that was derived from the human pro-inflammatory CD44 protein, could protect model nematodes from the toxicity of aggregative proteins that underlie the development of neurodegenerative disorders in humans. We found that the 5MER peptide mitigates the toxicity that stems from both; the AD-causing Aβ peptide and a stretch of poly-glutamine that is accountable for the development of several disorders including HD, while minimally affecting lifespan. This protection was dependent on the activity of aging-regulating transcription factors and associated with enhanced Aβ and polyQ35-YFP aggregation. A transcriptomic analysis unveiled that the peptide modifies signaling pathways, thereby modulating the expression of various genes, including these, which are known as protein homeostasis (proteostasis) regulators such as txt-13 and modifiers of proteasome activity. The knockdown of txt-13 protects worms from proteotoxicity to the same extent as the 5MER peptide, suggesting that the peptide activates the transcellular chaperone signaling to promote proteostasis. Together, our results propose that the 5MER peptide should be considered as a component of future therapeutic cocktails for the treatment of neurodegenerative maladies.
Yehezkel AS, Abudi N, Nevo Y, Benyamini H, Elgavish S, Weinstock M, Abramovitch R. AN1284 attenuates steatosis, lipogenesis, and fibrosis in mice with pre-existing non-alcoholic steatohepatitis and directly affects aryl hydrocarbon receptor in a hepatic cell line. Front Endocrinol (Lausanne) 2023;14:1226808.
Non-alcoholic steatohepatitis (NASH) is an aggressive form of fatty liver disease with hepatic inflammation and fibrosis for which there is currently no drug treatment. This study determined whether an indoline derivative, AN1284, which significantly reduced damage in a model of acute liver disease, can reverse steatosis and fibrosis in mice with pre-existing NASH and explore its mechanism of action. The mouse model of dietary-induced NASH reproduces most of the liver pathology seen in human subjects. This was confirmed by RNA-sequencing analysis. The Western diet, given for 4 months, caused steatosis, inflammation, and liver fibrosis. AN1284 (1 mg or 5 mg/kg/day) was administered for the last 2 months of the diet by micro-osmotic-pumps (mps). Both doses significantly decreased hepatic damage, liver weight, hepatic fat content, triglyceride, serum alanine transaminase, and fibrosis. AN1284 (1 mg/kg/day) given by mps or in the drinking fluid significantly reduced fibrosis produced by carbon tetrachloride injections. In human HUH7 hepatoma cells incubated with palmitic acid, AN1284 (2.1 and 6.3 ng/ml), concentrations compatible with those in the liver of mice treated with AN1284, decreased lipid formation by causing nuclear translocation of the aryl hydrocarbon receptor (AhR). AN1284 downregulated fatty acid synthase (FASN) and sterol regulatory element-binding protein 1c (SREBP-1c) and upregulated Acyl-CoA Oxidase 1 and Cytochrome P450-a1, genes involved in lipid metabolism. In conclusion, chronic treatment with AN1284 (1mg/kg/day) reduced pre-existing steatosis and fibrosis through AhR, which affects several contributors to the development of fatty liver disease. Additional pathways are also influenced by AN1284 treatment.
Haran A, Bergel M, Kleiman D, Hefetz L, Israeli H, Weksler-Zangen S, Agranovich B, Abramovich I, Ben-Haroush Schyr R, Gottlieb E, Ben-Zvi D. Differential effects of bariatric surgery and caloric restriction on hepatic one-carbon and fatty acid metabolism. iScience 2023;26(7):107046.
Weight loss interventions, including dietary changes, pharmacotherapy, or bariatric surgery, prevent many of the adverse consequences of obesity, and may also confer intervention-specific benefits beyond those seen with decreased weight alone. We compared the molecular effects of different interventions on liver metabolism to understand the mechanisms underlying these benefits. Male rats on a high-fat, high-sucrose diet underwent sleeve gastrectomy (SG) or intermittent fasting with caloric restriction (IF-CR), achieving equivalent weight loss. The interventions were compared to (AL)-fed controls. Analysis of liver and blood metabolome and transcriptome revealed distinct and sometimes contrasting metabolic effects between the two interventions. SG primarily influenced one-carbon metabolic pathways, whereas IF-CR increased lipogenesis and glycogen storage. These findings suggest that the unique metabolic pathways affected by SG and IF-CR contribute to their distinct clinical benefits, with bariatric surgery potentially influencing long-lasting changes through its effect on one-carbon metabolism.
Srivastava R, Horwitz M, Hershko-Moshe A, Bronstein S, Ben-Dov IZ, Melloul D. Posttranscriptional regulation of the prostaglandin E receptor spliced-isoform EP3-γ and its implication in pancreatic β-cell failure. FASEB J 2023;37(6):e22958.
In Type 2 diabetes (T2D), elevated lipid levels have been suggested to contribute to insulin resistance and β-cell dysfunction. We previously reported that the expression of the PGE2 receptor EP3 is elevated in islets of T2D individuals and is preferentially stimulated by palmitate, leading to β-cell failure. The mouse EP3 receptor generates three isoforms by alternative splicing which differ in their C-terminal domain and are referred to as mEP3α, mEP3β, and mEP3γ. We bring evidence that the expression of the mEP3γ isoform is elevated in islets of diabetic db/db mice and is selectively upregulated by palmitate. Specific knockdown of the mEP3γ isoform restores the expression of β-cell-specific genes and rescues MIN6 cells from palmitate-induced dysfunction and apoptosis. This study indicates that palmitate stimulates the expression of the mEP3γ by a posttranscriptional mechanism, compared to the other spliced isoforms, and that the de novo synthesized ceramide plays an important role in FFA-induced mEP3γ expression in β-cells. Moreover, induced levels of mEP3γ mRNA by palmitate or ceramide depend on p38 MAPK activation. Our findings suggest that mEP3γ gene expression is regulated at the posttranscriptional level and defines the EP3 signaling axis as an important pathway mediating β-cell-impaired function and demise.