Biology subjects

wu, x.

Publications and source records attributed to wu, x..

7 recordsLinked to original sources

bioRxiv2026

The U6 snRNA capping enzyme Amus/MePCE is required for the stability of U6atac and the processing of introns with features of both major and minor classes

Over 99% of the introns in humans are removed by the major spliceosome with the U6 snRNA as the catalytic component while the rest 1% by the minor spliceosome containing U6atac. Recent evidence supports mechanistic interactions between the two splicing pathways even though they have been considered as operating in parallel. Here we report a unique genetic condition in which both splicing pathways are partially impaired, and present evidence supporting inter-pathway interactions. We recently showed that the Drosophila Amus protein and its mammalian homolog MePCE serve as the methyltransferase of U6 and protect its stability. We show here that U6atac is greatly reduced under the same amus or mepce mutant backgrounds, suggesting Amus/MePCE serves the same protective function for U6atac. Interestingly, the processing of canonical minor introns is not significantly affected in the mutants, suggesting that a minimal amount of U6atac is sufficient for those reactions. In contrast, the splicing of a second class of minor spliceosome sensitive introns are inhibited. These introns harbor splice sites different from the minor consensus even though they interact favorably with the minor spliceosome as shown by others. Interestingly, most members of this class of minor-like introns are evolutionarily younger than their canonical counterparts, and our in-depth analysis of one such intron supports that some of them might be functionally neutral. Our study provides empirical evidence supporting the existence of a class of introns jointly regulated by the two splicing pathways, and revealing additional complexity in the functional evolution of minor splicing.

genetics↗

bioRxiv2026

Ripk1 Deficiency or K376R Mutation in Dendritic Cells Promotes Potent Antitumor Immunity

Dendritic cells (DCs) are critical for initiating adaptive immunity through antigen presentation and T cell priming. While immunogenic cell death (ICD) enhances anti-tumor immunity, how programmed cell death in DCs shapes tumor immune responses remains unclear. Receptor-interacting protein kinase 1 (RIPK1) regulates apoptosis, necroptosis, and inflammation. Here, we show that mice with disrupted RIPK1 ubiquitination on K376 (Ripk1fl/K376R Cd11c-Cre, Ripk1DC-KO/K376R) develop inflammation and autoimmunity, phenocopying DC-specific RIPK1-deficient(Ripk1fl/fl Cd11c-Cre, Ripk1DC-KO) mice. These phenotypes were rescued by the genetic ablation of Ripk3 or Mlkl, establishing that RIPK1 ubiquitination is essential for suppressing DC necroptosis to maintain immune homeostasis. Remarkably, both Ripk1DC-KO and Ripk1DC-KO/K376R mice exhibit robust resistance to tumor growth, characterized by significantly enhanced T cell infiltration and activation. Mechanistically, we show that Ripk1 deficiency or the loss of its K376 ubiquitination augments antigen-presenting capacity of DCs through both necroptosis-dependent and -independent pathways. Furthermore, adoptive transfer of T cells from Ripk1DC-KO mice further amplifies anti-tumor immunity in recipient hosts. These results identify RIPK1 as a critical immunological checkpoint in DCs that constrains their immunogenic potential. Targeting this pathway represents a promising therapeutic strategy to potentiate T cell-mediated cancer immunotherapy.

immunology↗

bioRxiv2025

Curcumin Analogues Trigger HMOX1-Mediated Ferroptosis to Halt Endometrial Cancer Growth

BackgroundAdvanced endometrial cancer remains challenging to treat due to limited therapeutic options and drug resistance. Ferroptosis, an iron-dependent form of cell death, offers a potential strategy for overcoming resistance. Curcumin analogues with improved bioavailability, such as HO-3867 and AKT-100, exhibit potent anti-cancer activity, but their mechanisms remain under-explored. MethodsKLE, Hec50co and Ishikawa endometrial cancer cells were treated with HO-3867 or AKT-100. RNA sequencing, qPCR, and immunoblotting assessed ferroptosis-related gene expression, focusing on HMOX1. Intracellular iron and ROS were measured via FerroOrange and DCFH-DA staining. Cytotoxicity and colony formation were evaluated using CyQUANT assays, with pharmacological inhibitors (ZnPP, Liproxstatin-1, Z-VAD-FMK) and HMOX1 siRNA to dissect the roles of ferroptosis and apoptosis. ResultsBoth analogues upregulated multiple ferroptosis genes, prominently HMOX1. AKT-100 increased intracellular iron and ROS levels. Inhibition of HMOX1, ferroptosis, or apoptosis partially rescued cell viability, while HMOX1 knockdown enhanced clonogenic growth, confirming its key role in AKT-100-mediated cytotoxicity. ConclusionsHO-3867 and AKT-100 induce HMOX1-mediated ferroptosis and apoptosis, effectively suppressing endometrial cancer cell growth. These findings support the therapeutic potential of curcumin analogues and provide a foundation for in vivo studies targeting HMOX1 in endometrial cancer. O_FIG O_LINKSMALLFIG WIDTH=187 HEIGHT=200 SRC="FIGDIR/small/689080v1_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@610bcorg.highwire.dtl.DTLVardef@34d8eaorg.highwire.dtl.DTLVardef@18d2a5aorg.highwire.dtl.DTLVardef@d7b4f3_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2023

Requirement of GrgA for Chlamydia infectious progeny production, optimal growth, and efficient plasmid maintenance

Chlamydia, an obligate intracellular bacterial pathogen, has a unique developmental cycle involving the differentiation of invading elementary bodies (EBs) to noninfectious reticulate bodies (RBs), replication of RBs, and redifferentiation of RBs into progeny EBs. Progression of this cycle is regulated by three sigma factors, which direct the RNA polymerase to their respective target gene promoters. We hypothesized that the Chlamydia-specific transcriptional regulator GrgA, previously shown to activate {sigma}66 and {sigma}28, plays an essential role in chlamydial development and growth. To test this hypothesis, we applied a novel genetic tool known as dependence on plasmid-mediated expression (DOPE) to create Chlamydia trachomatis with conditional GrgA-deficiency. We show that GrgA-deficient C. trachomatis RBs have a growth rate that is approximately half of the normal rate and fail to transition into progeny EBs. In addition, GrgA-deficient C. trachomatis fail to maintain its virulence plasmid. Results of RNA-seq analysis indicate that GrgA promotes RB growth by optimizing tRNA synthesis and expression of nutrient-acquisition genes, while it enables RB-to-EB conversion by facilitating the expression of a histone and outer membrane proteins required for EB morphogenesis. GrgA also regulates numerous other late genes required for host cell exit and subsequent EB invasion into host cells. Importantly, GrgA stimulates the expression of {sigma}54, the third and last sigma factor, and its activator AtoC, and thereby indirectly upregulating the expression of {sigma}54-dependent genes. In conclusion, our work demonstrates that GrgA is a master transcriptional regulator in Chlamydia and plays multiple essential roles in chlamydial pathogenicity. IMPORTANCEHallmarks of the developmental cycle of the obligate intracellular pathogenic bacterium Chlamydia are the primary differentiation of the infectious elementary body (EB) into the proliferative reticulate body (RB) and the secondary differentiation of RBs back into EBs. The mechanisms regulating these transitions remain unclear. In this report, we developed an effective novel strategy termed DOPE that allows for the knockdown of essential genes in Chlamydia. We demonstrate that GrgA, a Chlamydia-specific transcription factor, is essential for the secondary differentiation and optimal growth of RBs. We also show that GrgA, a chromosome-encoded regulatory protein, controls the maintenance of the chlamydial virulence plasmid. Transcriptomic analysis further indicates that GrgA functions as a critical regulator of all three sigma factors that recognize different promoter sets at developmental stages. The DOPE strategy outlined here should provide a valuable tool for future studies examining chlamydial growth, development, and pathogenicity.

microbiology↗

bioRxiv2021

AAV-Mediated In Vivo CAR Gene Therapy for Targeting Human T Cell Leukemia

Chimeric antigen receptor (CAR) T cell therapy is the most active field in immuno-oncology and brings substantial benefit to patients with B cell malignancies. However, the complex procedure for CAR T cell generation hampers its widespread applications. Here, we describe a novel approach in which human CAR T cells can be generated within the host upon injecting an Adeno-associated virus (AAV)vector carrying the CAR gene, which we call AAV delivering CAR gene therapy (ACG). Upon single infusion into a humanized NCG tumor mouse model of human T cell leukemia, AAV generates sufficient numbers of potent in vivo CAR cells, resulting in tumor regression; these in vivo generated CAR cells produce antitumor immunological characteristics. This instantaneous generation of in vivo CAR T cells may bypass the need for patient lymphodepletion, as well as the ex vivo processes of traditional CAR T cell production, which may make CAR therapy simpler and less expensive. It may allow the development of intricate, individualized treatments in the form of on-demand and diverse therapies. Significance StatementAAV can generate enough CAR cells within the host. That act as a living drug, distributed throughout the body, and persist for weeks, with the ability to recognize and destroy tumor cells.

immunology↗

bioRxiv2020

The selfish nature in interpersonal exchange among adolescents: imposing the kind and submitting to the exploitative

Cooperation is essential for success in society. Research consistently showed that adolescents are less cooperative than adults, which is often attributed to underdeveloped mentalizing that limits their expectations of others. However, the internal computations underlying this reduced cooperation remain largely unexplored. This study compared cooperation between adolescents and adults using a repeated Prisoners Dilemma Game. Adolescents cooperated less than adults, particularly after their partners cooperation. Computational modeling revealed that adults increased their intrinsic reward for reciprocating when their partner continued cooperating, a pattern absent in adolescents. Both computational modeling and self-reported ratings showed that adolescents did not differ from adults in building expectations of their partners cooperation. Therefore, the reduced cooperation appears driven by a lower intrinsic reward for reciprocity, reflecting a stronger motive to prioritize self-interest, rather than a deficiency in predicting others cooperation in social learning. These findings provide insights into the developmental trajectory of cooperation from adolescence to adulthood.

animal behavior and cognition↗

bioRxiv2020

Celastrol directly inhibits PFKM to induce weight loss and leptin sensitization

Despite the prevalence of obesity and related health consequences around the globe, effective treatments for inducing healthy weight loss are still lacking. Celastrol is a pentacyclic triterpene that was recently identified as a potent anti-obesity agent. Celastrol increases sensitivity to leptin, but the molecular target of celastrol is unknown. Therefore, the mechanisms by which this agent exerts its anti-obesity effect remain elusive. Using tissue-specific ABPP (activity-based protein profiling), we found that PFKM, a rate-limiting enzyme for glycolysis in skeletal muscle, is a direct target of celastrol. Celastrol inhibited PFKM enzymatic activity, and Pfkm knockout mice were resistant to a high fat diet, were hypersensitive to exogenous leptin, and were unresponsive to celastrol. PFKM inhibition led to activation of AMPK and inactivation of ACC in cultured myotubes and mouse skeletal muscle. Specific loss of AMPK in muscle significantly attenuated the anti-obesity effects of celastrol. Further, PFKM inhibition and subsequent activation of the AMPK/ACC signaling pathway reduced levels of free fatty acids by switching energy expenditure and consequently decreasing levels of SOCS1 expression, which are both required for leptin sensitization in 293t/hLepRb cells and mice. Finally, using a high throughput compound screen we identified an alternative PFKM inhibitor, 3-79, which exhibits a strong anti-obesity effect and non-covalent binding capacity. This compound is a promising agent for treating obesity in the clinic.

physiology↗