Biology subjects

Plaschkes, I.

Publications and source records attributed to Plaschkes, I..

4 recordsLinked to original sources

bioRxiv2026

Peripheral CB1R Blockade Suppresses AKI-to-CKD Maladaptive Repair

BackgroundAcute kidney injury (AKI) frequently progresses to chronic kidney disease (CKD), yet mechanisms governing this transition remain poorly understood. The endocannabinoid system (ECS), particularly cannabinoid-1 receptor (CB1R), regulates inflammation and metabolism in various organs, but its role in post-AKI maladaptive repair is less established. MethodsWe analyzed CB1R expression in kidney biopsies from pre- and post-transplant recipients and in murine AKI models (ischemia-reperfusion injury [IRI] and folic acid [FA]-induced AKI). Peripheral CB1R blockade was evaluated in FA-AKI model and in human primary kidney proximal tubule cells (hKPTCs). Spatial metabolomics, semi-targeted metabolomic profiling, and gene and protein expression characterized molecular mechanisms. ResultsCB1R expression was increased in kidneys undergoing maladaptive repair in both humans and mice, but remained unchanged during acute injury. In the FA-induced AKI model, the ECS showed stage-specific alterations, with temporal and spatial fluctuations in endocannabinoid levels and their enzymatic regulators. Peripheral CB1R blockade during the repair phase preserved kidney function, reduced injury, and maintained systemic glucose homeostasis. Metabolomic and molecular analyses revealed that CB1R blockade restored dysregulated arginine metabolism and reduced AKT/NF-{kappa}B-p65 pathway in post-AKI kidneys, linking CB1R activation to inflammatory signaling. In hKPTCs, 2-AG-induced activation of CB1R increased VCAM1 expression, a failed-repair marker, while its antagonism reduced TNF/2-AG-induced expression of pro-inflammatory adhesion molecules, chemokines, cytokines, and arginine metabolism enzymes. ConclusionsCB1R overactivation drives AKI-to-CKD progression by promoting inflammatory signaling and metabolic dysregulation. Peripheral CB1R blockade during the repair phase represents a novel therapeutic strategy to prevent maladaptive repair and CKD development after AKI. These findings establish CB1R as a phase-specific therapeutic target for post-AKI intervention. Translational StatementPeripheral CB1R antagonists offer a first-in-class therapeutic strategy to halt progression from acute kidney injury (AKI) to chronic kidney disease (CKD) by selectively targeting maladaptive tubular repair. By blocking CB1R signaling specifically in the kidney, these agents attenuate inflammation, metabolic dysregulation, and fibrogenic pathways that drive failed repair, while sparing central nervous system CB1R and thereby minimizing neuropsychiatric adverse effects. This phase-specific, peripherally restricted approach supports the development of peripheral CB1R antagonists as a viable translational therapy to improve long-term renal outcomes after AKI.

pharmacology and toxicology↗

bioRxiv2024

Transcriptome analysis of atad3-null zebrafish embryos elucidates possible disease mechanisms

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. To further investigate the gene function and its implication in health and disease, we utilized CRISPR/Cas9 genome editing to generate a knockout (KO) model of the zebrafish ortholog gene, atad3. Analysis of atad3-null zebrafish embryos revealed microcephaly, small eyes, pericardial edema and musculature thinning, closely mirroring with 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. 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.

genetics↗

bioRxiv2022

Hematopoiesis and cell growth are differentially regulated by TAL1 isoforms

T-cell acute lymphoblastic leukemia (T-ALL) protein 1 (TAL1) is a central transcription factor in hematopoiesis. The timing and level of TAL1 expression orchestrate the differentiation to specialized blood cells and its overexpression is a common cause of T-ALL. Here we studied the two protein isoforms of TAL1, short and long, that are generated by the use of alternative promoters as well as by alternative splicing. We analyzed the expression of each isoform by deleting an enhancer or insulator, or by opening chromatin at the enhancer location. Our results show that each enhancer promotes expression from a specific TAL1 promoter. Expression from a specific promoter gives rise to a unique 5 UTR with differential regulation of translation. Moreover, our study suggests that the enhancers regulate TAL1 exon 3 alternative splicing by inducing changes in the chromatin at the splice site, which we demonstrate is mediated by KMT2B. Furthermore, our results indicate that TAL1-short binds more strongly to TAL1 E-protein partners and functions as a stronger transcription factor than TAL1-long. Specifically TAL1-short has a unique transcription signature promoting apoptosis. Finally, when we expressed both isoforms in mice bone-marrow, we found that while overexpression of both isoforms prevents lymphoid differentiation, expression of TAL-short alone leads to hematopoietic stem cell exhaustion. Furthermore, we found that TAL1-short promoted erythropoiesis and reduced cell survival in the CML cell line K562. While TAL1 and its partners are considered promising therapeutic targets in the treatment of T-ALL, our results show that TAL1-short could act as a tumor suppressor and suggest that altering TAL1 isoforms ratio could be a preferred therapeutic approach.

molecular biology↗

bioRxiv2022

Depletion of FH, an essential TCA cycle enzyme, drives proliferation in a two-step model

Several tumor suppressor genes do not follow the canonical function of cell cycle repressors. For example, fumarate hydratase (FH) is an evolutionary conserved TCA cycle enzyme that reversibly catalyzes the hydration of fumarate to L-malate and has a moonlight function in the DNA damage response (DDR). Interestingly, despite this enzymes essential role in central carbon metabolism, FH is inactive or absent in several tumors, such as hereditary leiomyomatosis and renal cell cancer (HLRCC). Accordingly, FH has a contradictory cellular function, as it is pro-survival through its role in the TCA cycle, yet its loss can drive tumorigenesis. These observations have supported the role of FH as a tumor suppressor. Here, we solved this contradiction by determining the molecular mechanisms that allow the cells to survive and even proliferate upon FH loss. We found that the cells response to FH loss is separated into two distinct time frames based on cell proliferation and DNA damage repair. During the early stages of FH loss, the cells proliferation and DNA damage repair are inhibited. However, over time the cells overcome the FH loss and form knockout clones, indistinguishable from WT cells in their proliferation rate. Due to the FH loss effect on DNA damage repair, we assumed that the recovered cells bear adaptive mutations. Therefore, we applied whole-exome sequencing to identify such mutated genes systematically. Indeed, we identified recurring mutations in genes belonging to the central oncogenic signaling pathways, such as JAK/STAT, which we validated to be impaired in FH-KO clones. Intriguingly, we demonstrated that these adaptive mutations are responsible for FH-KO cell proliferation under TCA cycle malfunction.

cancer biology↗