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The Journal of Biological Chemistry May 2024While the deubiquitinase ATXN3 has been implicated as a potential oncogene in various types of human cancers, its role in colon adenocarcinoma remains understudied....
While the deubiquitinase ATXN3 has been implicated as a potential oncogene in various types of human cancers, its role in colon adenocarcinoma remains understudied. Surprisingly, our findings demonstrate that ATXN3 exerts an anti-tumor effect in human colon cancers through potentiating Galectin-9-induced apoptosis. CRISPR-mediated ATXN3 deletion unexpectedly intensified colon cancer growth both in vitro and in xenograft colon cancers. At the molecular level, we identified ATXN3 as a bona fide deubiquitinase specifically targeting Galectin-9, as ATXN3 interacted with and inhibited Galectin-9 ubiquitination. Consequently, targeted ATXN3 ablation resulted in reduced Galectin-9 protein expression, thereby diminishing Galectin-9-induced colon cancer apoptosis and cell growth arrest. The ectopic expression of Galectin-9 fully reversed the growth of ATXN3-null colon cancer in mice. Furthermore, immunohistochemistry staining revealed a significant reduction in both ATXN3 and Galectin-9 protein expression, along with a positive correlation between them in human colon cancer. Our study identifies the first Galectin-9-specific deubiquitinase and unveils a tumor-suppressive role of ATXN3 in human colon cancer.
PubMed: 38815863
DOI: 10.1016/j.jbc.2024.107415 -
Cell Reports May 2024The protozoan parasite Cryptosporidium is a leading cause of diarrhea in young children. The parasite's life cycle involves a coordinated and timely progression from...
The protozoan parasite Cryptosporidium is a leading cause of diarrhea in young children. The parasite's life cycle involves a coordinated and timely progression from asexual to sexual stages, leading to the formation of the transmissible oocyst. Underlying molecular signaling mechanisms orchestrating sexual development are not known. Here, we describe the function of a signaling kinase in Cryptosporidium male gametogenesis. We reveal the expression of Cryptosporidium parvum calcium-dependent protein kinase 5 (CDPK5) during male gamete development and its important role in the egress of mature gametes. Genetic ablation of this kinase results in viable parasites, indicating that this gene is dispensable for parasite survival. Interestingly, cdpk5 deletion decreases parasite virulence and impacts oocyst shedding in immunocompromised mice. Using phosphoproteomics, we identify possible CDPK5 substrates and biological processes regulated by this kinase. Collectively, these findings illuminate parasite cell biology by revealing a mechanism controlling male gamete production and a potential target to block disease transmission.
PubMed: 38814783
DOI: 10.1016/j.celrep.2024.114263 -
ELife May 2024Neurexins play diverse functions as presynaptic organizers in various glutamatergic and GABAergic synapses. However, it remains unknown whether and how neurexins are...
Neurexins play diverse functions as presynaptic organizers in various glutamatergic and GABAergic synapses. However, it remains unknown whether and how neurexins are involved in shaping functional properties of the glycinergic synapses, which mediate prominent inhibition in the brainstem and spinal cord. To address these issues, we examined the role of neurexins in a model glycinergic synapse between the principal neuron in the medial nucleus of the trapezoid body (MNTB) and the principal neuron in the lateral superior olive (LSO) in the auditory brainstem. Combining RNAscope with stereotactic injection of AAV-Cre in the MNTB of neurexin1/2/3 conditional triple knockout mice, we showed that MNTB neurons highly express all isoforms of neurexins although their expression levels vary remarkably. Selective ablation of all neurexins in MNTB neurons not only reduced the amplitude but also altered the kinetics of the glycinergic synaptic transmission at LSO neurons. The synaptic dysfunctions primarily resulted from an impaired Ca sensitivity of release and a loosened coupling between voltage-gated Ca channels and synaptic vesicles. Together, our current findings demonstrate that neurexins are essential in controlling the strength and temporal precision of the glycinergic synapse, which therefore corroborates the role of neurexins as key presynaptic organizers in all major types of fast chemical synapses.
Topics: Animals; Mice, Knockout; Glycine; Mice; Trapezoid Body; Synaptic Transmission; Neural Cell Adhesion Molecules; Superior Olivary Complex; Brain Stem; Synapses; Neurons; Cell Adhesion Molecules, Neuronal; Nerve Tissue Proteins; Neurexins; Calcium-Binding Proteins
PubMed: 38814174
DOI: 10.7554/eLife.94315 -
World Journal of Gastroenterology May 2024Contrast-enhanced endoscopic ultrasound (CH-EUS) can overcome the limitations of endoscopic ultrasound-guided acquisition by identifying microvessels inside... (Review)
Review
Contrast-enhanced endoscopic ultrasound (CH-EUS) can overcome the limitations of endoscopic ultrasound-guided acquisition by identifying microvessels inside inhomogeneous tumours and improving the characterization of these tumours. Despite the initial enthusiasm that oriented needle sampling under CH-EUS guidance could provide better diagnostic yield in pancreatic solid lesions, further studies did not confirm the supplementary values in cases of tissue acquisition guided by CH-EUS. This review details the knowledge based on the available data on contrast-guided procedures. The indications for CH-EUS tissue acquisition include isoechoic EUS lesions with poor visible delineation where CH-EUS can differentiate the lesion vascularisation from the surrounding parenchyma and also the mural nodules within biliopancreatic cystic lesions, which occur in select cases. Additionally, the roles of CH-EUS-guided therapy in patients whose pancreatic fluid collections or bile ducts that have an echogenic content have indications for drainage, and patients who have nonvisualized vessels that need to be highlighted Doppler EUS are presented. Another indication is represented if there is a need for an immediate assessment of the post-radiofrequency ablation of pancreatic neuroendocrine tumours, in which case CH-EUS can be used to reveal the incomplete tumour destruction.
Topics: Humans; Contrast Media; Pancreatic Neoplasms; Endosonography; Pancreas; Endoscopic Ultrasound-Guided Fine Needle Aspiration; Ultrasonography, Interventional; Drainage; Pancreatic Diseases
PubMed: 38813054
DOI: 10.3748/wjg.v30.i17.2311 -
Research (Washington, D.C.) 20244,4-Dimethylsterols constitute a unique class of phytosterols responsible for regulating endogenous cannabinoid system (ECS) functions. However, precise mechanism...
4,4-Dimethylsterols constitute a unique class of phytosterols responsible for regulating endogenous cannabinoid system (ECS) functions. However, precise mechanism through which 4,4-dimethylsterols affect fat metabolism and the linkage to the ECS remain unresolved. In this study, we identified that 4,4-dimethylsterols, distinct from 4-demethseterols, act as inhibitors of fatty acid amide hydrolases (FAAHs) both in vivo and in vitro. Genetic ablation of FAAHs () abolishes the effects of 4,4-dimethylsterols on fat accumulation and locomotion behavior in a model. We confirmed that dietary intervention with 4,4-dimethylsterols in a high-fat diet (HFD) mouse model leads to a significant reduction in body weight (>11.28%) with improved lipid profiles in the liver and adipose tissues and increased fecal triacylglycerol excretion. Untargeted and targeted metabolomics further verified that 4,4-dimethylsterols influence unsaturated fatty acid biosynthesis and elevate oleoyl ethanolamine levels in the intestine. We propose a potential molecular mechanism in which 4,4-dimethylsterols engage in binding interactions with the catalytic pocket (Ser241) of FAAH-1 protein due to the shielded polarity, arising from the presence of 2 additional methyl groups (CH). Consequently, 4,4-dimethylsterols represent an unexplored class of beneficial phytosterols that coordinate with FAAH-1 activity to reduce fat accumulation, which offers new insight into intervention strategies for treating diet-induced obesity.
PubMed: 38812531
DOI: 10.34133/research.0377 -
Clinical Cardiology Jun 2024The purpose of this study was to explore the association between triglycerides (TGs) and the risk of atrial fibrillation (AF) recurrence.
BACKGROUND
The purpose of this study was to explore the association between triglycerides (TGs) and the risk of atrial fibrillation (AF) recurrence.
METHODS AND RESULTS
Included were adult patients with AF who underwent radiofrequency catheter ablation in the Affiliated Changzhou Second People's Hospital of Nanjing Medical University. The enrolled patients were divided into the AF recurrence group and the sinus rhythm (SR) maintenance group. The univariate Cox regression analysis and Kaplan-Meier survival curve were performed estimate the association between TG and the risk of AF recurrence. Of the 402 patients, 79 (19.7%) experienced recurrence of AF after ablation. The TG level was significantly higher in the AF recurrence group than in the SR-maintaining group. Patients were grouped by quartile of TG levels, with Quartile 1 and Quartile 2 defined as the low concentration group, Quartile 3 as the moderate concentration group, and Quartile 4 as the high concentration group. Multivariate Cox regression analysis showed that the moderate concentration group (p = .02, hazard ratio [HR]: 2.331, 95% confidence interval [CI]: 1.141-4.762) and high concentration group (p = .007, HR: 2.873, 95% CI: 1.332-6.199) were associated with an increased risk of AF recurrence compared with the low concentration group. The median follow-up was 1.17 years, it is indicated that a higher risk of recurrent AF was observed in the moderate concentration and high concentration group (log-rank: χ = 7.540, p = .023).
CONCLUSION
Our data suggest that an elevated TG level measured before catheter ablation is associated with an increased risk of AF recurrence.
Topics: Humans; Atrial Fibrillation; Male; Female; Catheter Ablation; Retrospective Studies; Recurrence; Triglycerides; Middle Aged; Risk Factors; Biomarkers; China; Time Factors; Treatment Outcome; Risk Assessment; Aged; Follow-Up Studies
PubMed: 38812437
DOI: 10.1002/clc.24276 -
Variant-specific pathophysiological mechanisms of AFF3 differently influence transcriptome profiles.Genome Medicine May 2024We previously described the KINSSHIP syndrome, an autosomal dominant disorder associated with intellectual disability (ID), mesomelic dysplasia and horseshoe kidney,...
BACKGROUND
We previously described the KINSSHIP syndrome, an autosomal dominant disorder associated with intellectual disability (ID), mesomelic dysplasia and horseshoe kidney, caused by de novo variants in the degron of AFF3. Mouse knock-ins and overexpression in zebrafish provided evidence for a dominant-negative mode of action, wherein an increased level of AFF3 resulted in pathological effects.
METHODS
Evolutionary constraints suggest that other modes-of-inheritance could be at play. We challenged this hypothesis by screening ID cohorts for individuals with predicted-to-be damaging variants in AFF3. We used both animal and cellular models to assess the deleteriousness of the identified variants.
RESULTS
We identified an individual with a KINSSHIP-like phenotype carrying a de novo partial duplication of AFF3 further strengthening the hypothesis that an increased level of AFF3 is pathological. We also detected seventeen individuals displaying a milder syndrome with either heterozygous Loss-of-Function (LoF) or biallelic missense variants in AFF3. Consistent with semi-dominance, we discovered three patients with homozygous LoF and one compound heterozygote for a LoF and a missense variant, who presented more severe phenotypes than their heterozygous parents. Matching zebrafish knockdowns exhibit neurological defects that could be rescued by expressing human AFF3 mRNA, confirming their association with the ablation of aff3. Conversely, some of the human AFF3 mRNAs carrying missense variants identified in affected individuals did not rescue these phenotypes. Overexpression of mutated AFF3 mRNAs in zebrafish embryos produced a significant increase of abnormal larvae compared to wild-type overexpression further demonstrating deleteriousness. To further assess the effect of AFF3 variation, we profiled the transcriptome of fibroblasts from affected individuals and engineered isogenic cells harboring + / + , KINSSHIP/KINSSHIP, LoF/ + , LoF/LoF or KINSSHIP/LoF AFF3 genotypes. The expression of more than a third of the AFF3 bound loci is modified in either the KINSSHIP/KINSSHIP or the LoF/LoF lines. While the same pathways are affected, only about one third of the differentially expressed genes are common to the homozygote datasets, indicating that AFF3 LoF and KINSSHIP variants largely modulate transcriptomes differently, e.g. the DNA repair pathway displayed opposite modulation.
CONCLUSIONS
Our results and the high pleiotropy shown by variation at this locus suggest that minute changes in AFF3 function are deleterious.
Topics: Humans; Animals; Zebrafish; Transcriptome; Intellectual Disability; Phenotype; Female; Male; Mutation, Missense; Loss of Function Mutation
PubMed: 38811945
DOI: 10.1186/s13073-024-01339-y -
Scientific Reports May 2024The current study aimed to investigate the effect of Sox9-Cre-directed Nr5a1-conditional knockout (Sox9-Cre;Nr5a1) on adrenal development. We showed that SOX9 is...
The current study aimed to investigate the effect of Sox9-Cre-directed Nr5a1-conditional knockout (Sox9-Cre;Nr5a1) on adrenal development. We showed that SOX9 is expressed by adrenocortical cells at E10.5-E11.5 but is extinguished no later than E12.5. The number of adrenocortical cells significantly reduced in Sox9-Cre;Nr5a1 mice while the number of cleaved caspase 3-positive cells increased compared to that in the controls at E11.5-E12.5, when the adrenal primordium (AP) is about to expand. This indicated that fetal adrenocortical cells are lost via apoptosis due to Nr5a1 ablation by E12.5. Both medulla formation and encapsulation were perturbed, accompanied by a smaller AP size, in Sox9-Cre;Nr5a1 mice during embryonic development. Adult Sox9-Cre;Nr5a1 adrenals were hypoplastic and exhibited irregular organization of the medulla with aberrant sex differentiation in the X zone. Additionally, there were histologically eosin-negative vacuolated cells, which were negative for both the X-zone marker 20αHSD and the steroidogenesis marker 3βHSD at the innermost cortex of Sox9-Cre;Nr5a1 adrenals. Although Nr5a1 adrenals were hypoplastic, a small number of chromaffin cells were properly located in the center, having normal sex differences in the X-zone. The results collectively provided in-vivo evidence that Nr5a1 plays a critical role in AP expansion and subsequent adrenal development.
Topics: Animals; SOX9 Transcription Factor; Mice; Steroidogenic Factor 1; Adrenal Glands; Integrases; Mice, Knockout; Female; Male
PubMed: 38811798
DOI: 10.1038/s41598-024-63264-9 -
Nature Communications May 2024The IL-22RA1 receptor is highly expressed in the pancreas, and exogenous IL-22 has been shown to reduce endoplasmic reticulum and oxidative stress in human pancreatic...
The IL-22RA1 receptor is highly expressed in the pancreas, and exogenous IL-22 has been shown to reduce endoplasmic reticulum and oxidative stress in human pancreatic islets and promote secretion of high-quality insulin from beta-cells. However, the endogenous role of IL-22RA1 signaling on these cells remains unclear. Here, we show that antibody neutralisation of IL-22RA1 in cultured human islets leads to impaired insulin quality and increased cellular stress. Through the generation of mice lacking IL-22ra1 specifically on pancreatic alpha- or beta-cells, we demonstrate that ablation of murine beta-cell IL-22ra1 leads to similar decreases in insulin secretion, quality and islet regeneration, whilst increasing islet cellular stress, inflammation and MHC II expression. These changes in insulin secretion led to impaired glucose tolerance, a finding more pronounced in female animals compared to males. Our findings attribute a regulatory role for endogenous pancreatic beta-cell IL-22ra1 in insulin secretion, islet regeneration, inflammation/cellular stress and appropriate systemic metabolic regulation.
Topics: Animals; Insulin-Secreting Cells; Receptors, Interleukin; Female; Humans; Male; Insulin; Mice; Homeostasis; Glucose; Mice, Knockout; Insulin Secretion; Mice, Inbred C57BL; Interleukin-22; Glucose Intolerance; Interleukins; Aging
PubMed: 38811550
DOI: 10.1038/s41467-024-48320-2 -
Circulation Journal : Official Journal... May 2024It has not been fully elucidated which patients with persistent atrial fibrillation (PerAF) should undergo substrate ablation plus pulmonary vein isolation (PVI). This...
BACKGROUND
It has not been fully elucidated which patients with persistent atrial fibrillation (PerAF) should undergo substrate ablation plus pulmonary vein isolation (PVI). This study aimed to identify PerAF patients who required substrate ablation using intraprocedural assessment of the baseline rhythm and the origin of atrial fibrillation (AF) triggers.Methods and Results: This was a post hoc subanalysis using extended data of the EARNEST-PVI trial, a prospective multicenter randomized trial comparing PVI-alone and PVI-plus (i.e., PVI with added catheter ablation) arms. We divided 492 patients into 4 groups according to baseline rhythm and the location of AF triggers before PVI: Group A (n=22), sinus rhythm with pulmonary vein (PV)-specific AF triggers (defined as reproducible AF initiation from PVs only); Group B (n=211), AF with PV-specific AF triggers; Group C (n=94), sinus rhythm with no PV-specific AF trigger; Group D (n=165), AF with no PV-specific AF trigger. Among the 4 groups, only in Group D (AF at baseline and no PV-specific AF triggers) was arrhythmia-free survival significantly lower in the PVI-alone than PVI-plus arm (P=0.032; hazard ratio 1.68; 95% confidence interval 1.04-2.70).
CONCLUSIONS
Patients with sinus rhythm or PV-specific AF triggers did not receive any benefit from substrate ablation, whereas patients with AF and no PV-specific AF trigger benefited from substrate ablation.
PubMed: 38811199
DOI: 10.1253/circj.CJ-23-0936