Recurrent fever of unknown origin and unexplained bacteremia in a patient with a novel 4.5 Mb microdeletion in Xp11.23-p11.22.

Fever of unknown origin (FUO) remains a formidable diagnostic challenge in the field of medicine. Numerous studies suggest an association between FUO and genetic factors, including chromosomal abnormalities. Here, we report a female patient with a 4.5 Mb Xp microdeletion, who presented with recurrent FUO, bacteremia, colitis, and hematochezia. To elucidate the underlying pathogenic mechanism, we employed a comprehensive approach involving single cell RNA sequencing, T cell receptor sequencing, and flow cytometry to evaluate CD4 T cells. Analysis of peripheral blood mononuclear cells revealed augmented Th1, Th2, and Th17 cell populations, and elevated levels of proinflammatory cytokines in serum. Notably, the patient exhibited impaired Treg cell function, possibly related to deletion of genes encoding FOPX3 and WAS. Single cell analysis revealed specific expansion of cytotoxic CD4 T lymphocytes, characterized by upregulation of various signature genes associated with cytotoxicity. Moreover, interferon-stimulated genes were upregulated in the CD4 T effector memory cluster. Further genetic analysis confirmed maternal inheritance of the Xp microdeletion. The patient and her mother exhibited X chromosome-skewed inactivation, a potential protective mechanism against extensive X chromosome deletions; however, the mother exhibited complete skewing and the patient exhibited incomplete skewing (85:15), which may have contributed to emergence of immunological symptoms. In summary, this case report describes an exceptional instance of FUO stemming from an incompletely inactivated X chromosome microdeletion, thereby increasing our understanding of the genetics underpinning FUO.

Prion-like domain mediated phase separation of ARID1A promotes oncogenic potential of Ewing's sarcoma.

Liquid-liquid phase separation (LLPS) facilitates the formation of membraneless organelles within cells, with implications in various biological processes and disease states. AT-rich interactive domain-containing protein 1A (ARID1A) is a chromatin remodeling factor frequently associated with cancer mutations, yet its functional mechanism remains largely unknown. Here, we find that ARID1A harbors a prion-like domain (PrLD), which facilitates the formation of liquid condensates through PrLD-mediated LLPS. The nuclear condensates formed by ARID1A LLPS are significantly elevated in Ewing's sarcoma patient specimen. Disruption of ARID1A LLPS results in diminished proliferative and invasive abilities in Ewing's sarcoma cells. Through genome-wide chromatin structure and transcription profiling, we identify that the ARID1A condensate localizes to EWS/FLI1 target enhancers and induces long-range chromatin architectural changes by forming functional chromatin remodeling hubs at oncogenic target genes. Collectively, our findings demonstrate that ARID1A promotes oncogenic potential through PrLD-mediated LLPS, offering a potential therapeutic approach for treating Ewing's sarcoma.

Microglia Gravitate toward Amyloid Plaques Surrounded by Externalized Phosphatidylserine via TREM2.

Microglia play a crucial role in synaptic elimination by engulfing dystrophic neurons via triggering receptors expressed on myeloid cells 2 (TREM2). They are also involved in the clearance of beta-amyloid (Aß) plaques in Alzheimer's disease (AD); nonetheless, the driving force behind TREM2-mediated phagocytosis of beta-amyloid (Aß) plaques remains unknown. Here, using advanced 2D/3D/4D co-culture systems with loss-of-function mutations in TREM2 (a frameshift mutation engineered in exon 2) brain organoids/microglia/assembloids, it is identified that the clearance of Aß via TREM2 is accelerated by externalized phosphatidylserine (ePtdSer) generated from dystrophic neurons surrounding the Aß plaques. Moreover, it is investigated whether microglia from both sporadic (CRISPR-Cas9-based APOE4 lines) and familial (APPNL-G-F/MAPT double knock-in mice) AD models show reduced levels of TREM2 and lack of phagocytic activity toward ePtdSer-positive Aß plaques. Herein new insight is provided into TREM2-dependent microglial phagocytosis of Aß plaques in the context of the presence of ePtdSer during AD progression.

DNA methylome analysis reveals epigenetic alteration of complement genes in advanced metabolic dysfunction-associated steatotic liver disease.

Background/Aims: Blocking the complement system is a promising strategy to impede the progression of metabolic dysfunction-associated steatotic liver disease (MASLD). However, the interplay between complement and MASLD remains to be elucidated. This comprehensive approach aimed to investigate the potential association between complement dysregulation and the histological severity of MASLD. Methods: Liver biopsy specimens were procured from a cohort comprising 106 Korean individuals, which included 31 controls, 17 with isolated steatosis, and 58 with metabolic dysfunction-associated steatohepatitis (MASH). Utilizing the Infinium Methylation EPIC array, thorough analysis of methylation alterations in 61 complement genes was conducted. The expression and methylation of nine complement genes in a murine MASH model were examined using quantitative RT-PCR and pyrosequencing. Results: Methylome and transcriptome analyses of liver biopsies revealed significant (P <0.05) hypermethylation and downregulation of C1R, C1S, C3, C6, C4BPA, and SERPING1, as well as hypomethylation (P <0.0005) and upregulation (P <0.05) of C5AR1, C7, and CD59, in association with the histological severity of MASLD. Furthermore, DNA methylation and the relative expression of nine complement genes in a MASH diet mouse model aligned with human data. Conclusions: Our research provides compelling evidence that epigenetic alterations in complement genes correlate with MASLD severity, offering valuable insights into the mechanisms driving MASLD progression, and suggests that inhibiting the function of certain complement proteins may be a promising strategy for managing MASLD.

Comprehensive molecular characterization of TFE3-rearranged renal cell carcinoma.

TFE3-rearranged renal cell cancer (tRCC) is a rare form of RCC that involves chromosomal translocation of the Xp11.2 TFE3 gene. Despite its early onset and poor prognosis, the molecular mechanisms of the pathogenesis of tRCC remain elusive. This study aimed to identify novel therapeutic targets for patients with primary and recurrent tRCC. We collected 19 TFE3-positive RCC tissues that were diagnosed by immunohistochemistry and subjected them to genetic characterization to examine their genomic and transcriptomic features. Tumor-specific signatures were extracted using whole exome sequencing (WES) and RNA sequencing (RNA-seq) data, and the functional consequences were analyzed in a cell line with TFE3 translocation. Both a low burden of somatic single nucleotide variants (SNVs) and a positive correlation between the number of somatic variants and age of onset were observed. Transcriptome analysis revealed that four samples (21.1%) lacked the expected fusion event and clustered with the genomic profiles of clear cell RCC (ccRCC) tissues. The fusion event also demonstrated an enrichment of upregulated genes associated with mitochondrial respiration compared with ccRCC expression profiles. Comparison of the RNA expression profile with the TFE3 ChIP-seq pattern data indicated that PPARGC1A is a metabolic regulator of the oncogenic process. Cell proliferation was reduced when PPARGC1A and its related metabolic pathways were repressed by its inhibitor SR-18292. In conclusion, we demonstrate that PPARGC1A-mediated mitochondrial respiration can be considered a potential therapeutic target in tRCC. This study identifies an uncharacterized genetic profile of an RCC subtype with unique clinical features and provides therapeutic options specific to tRCC.

Melatonin alleviates myocardial dysfunction through inhibition of endothelial-to-mesenchymal transition via the NF-κB pathway.

Endothelial-to-mesenchymal transition (EndMT) is a complex biological process of cellular transdifferentiation by which endothelial cells (ECs) lose their characteristics and acquire mesenchymal properties, leading to cardiovascular remodeling and complications in the adult cardiovascular diseases environment. Melatonin is involved in numerous physiological and pathological processes, including aging, and has anti-inflammatory and antioxidant activities. This molecule is an effective therapeutic candidate for preventing oxidative stress, regulating endothelial function, and maintaining the EndMT balance to provide cardiovascular protection. Although recent studies have documented improved cardiac function by melatonin, the mechanism of action of melatonin on EndMT remains unclear. The present study investigated the effects of melatonin on induced EndMT by transforming growth factor-ß2/interleukin-1ß in both in vivo and in vitro models. The results revealed that melatonin reduced the migratory ability and reactive oxygen species levels of the cells and ameliorated mitochondrial dysfunction in vitro. Our findings indicate that melatonin prevents endothelial dysfunction and inhibits EndMT by activating related pathways, including nuclear factor kappa B and Smad. We also demonstrated that this molecule plays a crucial role in restoring cardiac function by regulating the EndMT process in the ischemic myocardial condition, both in vessel organoids and myocardial infarction (MI) animal models. In conclusion, melatonin is a promising agent that attenuates EC dysfunction and ameliorates cardiac damage compromising the EndMT process after MI.

Simple modeling of familial Alzheimer's disease using human pluripotent stem cell-derived cerebral organoid technology.

BACKGROUND: Cerebral organoids (COs) are the most advanced in vitro models that resemble the human brain. The use of COs as a model for Alzheimer's disease (AD), as well as other brain diseases, has recently gained attention. This study aimed to develop a human AD CO model using normal human pluripotent stem cells (hPSCs) that recapitulates the pathological phenotypes of AD and to determine the usefulness of this model for drug screening. METHODS: We established AD hPSC lines from normal hPSCs by introducing genes that harbor familial AD mutations, and the COs were generated using these hPSC lines. The pathological features of AD, including extensive amyloid-ß (Aß) accumulation, tauopathy, and neurodegeneration, were analyzed using enzyme-linked immunosorbent assay, Amylo-Glo staining, thioflavin-S staining, immunohistochemistry, Bielschowsky's staining, and western blot analysis. RESULTS: The AD COs exhibited extensive Aß accumulation. The levels of paired helical filament tau and neurofibrillary tangle-like silver deposits were highly increased in the AD COs. The number of cells immunoreactive for cleaved caspase-3 was significantly increased in the AD COs. In addition, treatment of AD COs with BACE1 inhibitor IV, a ß-secretase inhibitor, and compound E, a γ-secretase inhibitor, significantly attenuated the AD pathological features. CONCLUSION: Our model effectively recapitulates AD pathology. Hence, it is a valuable platform for understanding the mechanisms underlying AD pathogenesis and can be used to test the efficacy of anti-AD drugs.