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Targeting USP8 causes synthetic lethality through degradation of FGFR2 in ARID1A-deficient ovarian clear cell carcinoma

Over half of ovarian clear cell carcinoma (OCCC) cases exhibit deficiencies in the ARID1A gene, a chromatin remodeling complex component. OCCC is resistant to chemotherapy and challenging to treat, necessitating new drug treatment strategies. This study used a publicly available dependency factor database to identify synthetic lethal targets for ARID1A-deficient cancer. The DepMap portal was used to identify genes on which ARID1A-deficient cancer cell lines are highly dependent. Our analysis limited to ovarian cancer cell lines only identified the deubiquitinating enzyme USP8 as a synthetic lethal target in ARID1A-deficient OCCC cancer cell lines and mouse xenograft models. In addition, USP8 inhibitors were more selective for ARID1A-deficient cells than existing candidate drugs used in promising clinical trials for ARID1A-deficient cancers. Suppression of USP8 in ARID1A-deficient cells led to degradation of FGFR2 via the proteasome. Deficiency of ARID1A causes abnormalities in the STAT3 pathway, which is one of the downstream pathways of FGFR2, but suppression of USP8 attenuates phosphorylation of STAT3 pT705 and induces apoptosis. Taken together, our data suggest that USP8 is a novel therapeutic target for ARID1A-deficient OCCC and that USP8 inhibitors suppress FGFR2-STAT3 signaling.

Analysis of microbial composition and sharing in low-biomass human milk samples: a comparison of DNA isolation and sequencing techniques

Human milk microbiome studies are currently hindered by low milk bacterial/human cell ratios and often rely on 16S rRNA gene sequencing, which limits downstream analyses. Here, we aimed to find a method to study milk bacteria and assess bacterial sharing between maternal and infant microbiota. We tested four DNA isolation methods, two bacterial enrichment methods and three sequencing methods on mock communities, milk samples and negative controls. Of the four DNA isolation kits, the DNeasy PowerSoil Pro (PS) and MagMAX Total Nucleic Acid Isolation (MX) kits provided consistent 16S rRNA gene sequencing results with low contamination. Neither enrichment method substantially decreased the human metagenomic sequencing read-depth. Long-read 16S-ITS-23S rRNA gene sequencing biased the mock community composition but provided consistent results for milk samples, with little contamination. In contrast to 16S rRNA gene sequencing, 16S-ITS-23S rRNA gene sequencing of milk, infant oral, infant faecal and maternal faecal DNA from 14 mother-infant pairs provided sufficient resolution to detect significantly more frequent sharing of bacteria between related pairs compared to unrelated pairs. In conclusion, PS or MX kit-DNA isolation followed by 16S rRNA gene sequencing reliably characterises human milk microbiota, and 16S-ITS-23S rRNA gene sequencing enables studies of bacterial transmission in low-biomass samples.

TMEM41B is an endoplasmic reticulum Ca2+ release channel maintaining naive T cell quiescence and responsiveness

In mammalian cells, endoplasmic reticulum (ER) passively releases Ca2+ under steady state, but channels involved remain elusive. Here, we report that TMEM41B, an ER-resident membrane protein critical for autophagy, lipid metabolism, and viral infection, functions as an ER Ca2+ release channel. Biochemically, purified recombinant TMEM41B forms a concentration-dependent Ca2+ channel in single-channel electrophysiology assays. Cellularly, TMEM41B deficiency causes ER Ca2+ overload, while overexpression of TMEM41B depletes ER Ca2+. Immunologically, ER Ca2+ overload leads to upregulation of IL-2 and IL-7 receptors in naive T cells, which in turn increases basal signaling of JAK-STAT, AKT-mTOR, and MAPK pathways. This dysregulation drives TMEM41B-deficient naive T cells into a metabolically activated yet immunologically naive state. ER Ca2+ overload also downregulates CD5, lowering the activation threshold of TMEM41B-deficient T cells and leading to heightened T cell responses during infections. In summary, we identify TMEM41B as a concentration-dependent ER Ca2+ release channel, revealing an unexpected role of ER Ca2+ in naive T cell quiescence and responsiveness.

Biological, dietetic and pharmacological properties of vitamin B9

Humans must obtain vitamin B9 (folate) from plant-based diet. The sources as well as the effect of food processing are discussed in detail. Industrial production, fortification and biofortification, kinetics, and physiological role in humans are described. As folate deficiency leads to several pathological states, current opinions toward prevention through fortification are discussed. Claimed risks of increased folate intake are mentioned as well as analytical ways for measurement of folate.

Neonatal microbiome in the multiomics era: development and its impact on long-term health

The neonatal microbiome has been the focus of considerable research over the past two decades and studies have added fascinating information in terms of early microbial patterns and how these relate to various disease processes. One difficulty with the interpretation of these relationships is that such data is associative and provides little in terms of proof of causality or the underpinning mechanisms. Integrating microbiome data with other omics such as the proteome, inflammatory mediators, and the metabolome is an emerging approach to address this gap. Here we discuss these omics, their integration, and how they can be applied to improve our understanding, treatment, and prevention of disease.

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