Biology subjects

You, A.

Publications and source records attributed to You, A..

6 recordsLinked to original sources

bioRxiv2026

A PATHOGENIC NFKB2 VARIANT CAUSES COMBINED IMMUNODEFICIENCY WITH THYMIC AND PERIPHERAL LYMPHOID DEFECTS IN RATS

The non-canonical NF-kappa B pathway, in which NFKB2 plays a central role, is critical for lymphoid organ development and immune homeostasis. Pathogenic NFKB2 variants have been strongly associated with a broad spectrum of human pathologies, notably immunodysregulation syndromes, characterized by recurrent infections, autoantibody production and endocrine abnormalities. The mechanisms underlying the resulting immune defects remain incompletely understood. In the present study, we characterized the immune phenotype of a novel rat model harboring a Nfkb2 non-sense mutation located in the c-terminal region of the gene (c.2602T>A; p.Tyr867*, Nfkb2p.Tyr867*). This variant has been identified in patients with a familial form of common variable immunodeficiency (CVID) presenting with autoimmunity manifestations. Using this model, we demonstrate that mutated NFKB2 resulted in profound alterations of the thymic microenvironment, including reduced K5+ medullary thymic epithelial cells and decreased AIRE expression, accompanied by altered thymocyte development and impaired thymic regulatory T populations. Peripheral lymphoid organization was also profoundly affected, with absence of lymph nodes, defects in the splenic marginal zone, and alterations of CD4+ and CD8+ T-cell homeostasis, including impaired Treg populations and reduced ICOS expression on CD4+ T cells. The B-cell compartment was markedly altered, with impaired B-cell maturation, characterized by accumulation of IgM+IgD- transitional cells and a marked reduction of IgD+ mature B cells. These abnormalities were associated with impaired humoral immunity and complete absence of circulating immunoglobulins. Collectively, our findings define a systemic combined immunodeficiency phenotype in the Nfkb2-mutated rat, highlighting its utility for studying the role of non-canonical NF-kB signaling in immune system organization and adaptative immunity.

immunology↗

bioRxiv2026

Cross-species chromatin accessibility pinpoints HIVEP3 as a driver of thymic epithelial maturation and self-antigen expression, preventing chronic inflammation

Promiscuous expression of tissue-specific antigens (TSAs) by medullary thymic epithelial cells (mTECs) underpins central T-cell tolerance, relying on NF-{kappa}B-driven mTEC maturation and induction of the autoimmune regulator AIRE. However, a substantial fraction of TSAs is AIRE-independent, implying additional regulators that remain only partially identified. Using cross-species single-cell chromatin accessibility profiling of human and mouse TECs, we find that HIVEP motifs are among the most accessible regulatory elements across the mTEC lineage. Among HIVEP paralogs, HIVEP3 is robustly expressed in mature mTECs across human, mouse and rat; given that rat immunity more closely mirrors human physiology than the mouse, we generated a CRISPR Hivep3-knockout rat line. Hivep3 deletion impairs mTEC maturation, reduces Aire expression and reshapes the TSA repertoire that underlies negative selection and Treg induction, as Hivep3 constrains canonical NF-{kappa}B1 and sustains non-canonical NF-{kappa}B2, the principal mediator of mTEC maturation. Beyond mTECs, Hivep3 deficiency downregulates Foxn1 target genes in cortical TECs and impairs positive selection. In the periphery, Hivep3-KO rats show reduced splenic CD4 T-cells, a shift from naive towards effector-and central-memory phenotypes, increased regulatory T-cells, and a sustained Th1-biased serum profile (elevated IFN-{gamma}, reduced IL-17A) with concurrent systemic metabolic perturbations across all ages. With age, this culminates in chronic inflammation, with multi-organ CD3 T-cell infiltration accompanied by inflammatory lesions. Together, these findings establish HIVEP3 as a previously unrecognised regulator of thymic epithelial function and central tolerance, whose deficiency leads to systemic T-cell-mediated chronic inflammation.

immunology↗

bioRxiv2025

Lessons from a gene knockout mouse model: no phenotypes induced by deletion of the TPR4 domain of Ttc22

The TTC22 gene encodes a protein containing seven tetratricopeptide repeats (TPRs), which mediate protein-protein interactions as chaperones. We previously reported that the level of TTC22 transcript variant 1 (TTC22v1) was downregulated in human colon adenocarcinoma (COAD) and that TTC22 upregulated m6A-mediated WTAP and SNAI1 expression via the TTC22-RPL4 interaction and subsequently promoted COAD metastasis. Thus, a commercially available C57BL/6N mouse model in which the Ttc22 exon 2&3 encoding the TPR4 (equal to the human TTC22 TPR3) domain was knocked out via CRISPR-Cas9 was used to evaluate the contribution of Ttc22 to the development of mice and COAD. To determine the status of Ttc22 expression in Ttc22 knockout mice, we prepared a rabbit polyclonal antibody against the mouse Ttc22 protein, which could bind both wild type Ttc22 and TPR4-deleted Ttc22 proteins overexpressed in HEK293T cells, as determined by Western blot analysis. Ttc22 proteins were detected in colon tissue samples from wild-type mice and Ttc22 hemi-knockout (Ttc22 -/+) mice but not in those from fully Ttc22 knockout (Ttc22-/-) mice. Unfortunately, the long-term observation results demonstrated that Ttc22 knockout (KO, including Ttc22-/+ or Ttc22-/-) did not affect the body weight, development, fertility, or spontaneous tumor incidence of male or female mice. No differences in the incidence of AOM/DSS-induced COAD were observed between these mouse groups, although Ttc22 deletion partially resulted in the upregulation of genes related to the host adaptive response to inflammation in the colon mucosa. In conclusion, no phenotypes were induced by Ttc22 inactivation in C57BL/6N mice. HighlightsO_LIKnockout of Ttc22 exons 2 and 3 completely disrupted gene expression. C_LIO_LIKnockout of Ttc22 does not affect the development of C57BL mice. C_LIO_LIKnockout of Ttc22 does not affect the induction of mouse colon cancer by AOM/DSS. C_LI

molecular biology↗

bioRxiv2021

Multiple nucleotide polymorphism DNA markers for the accurate evaluation of genetic variations

DNA markers are an essential tool for the detection and evaluation of genetic variations, a central theme in genetics and biology. Effective markers must be highly reproducible, polymorphic, accurate and efficient to profile. We developed multiple dispersed nucleotide polymorphism (MNP) DNA marker and an efficient MNP genotyping method called MNP-Seq. The MNP marker was 17.48% more polymorphic than the highly polymorphic marker of microsatellites on a collection of hybrid rice plants. When applied to genotype more than 80,000 individual MNP markers of diploid rice and polyploidy hybrid cotton varieties which were notoriously difficult to genotype accurately, MNP-Seq finished in two days and achieved accuracies of 99.999% and 99.988%, respectively. We adopted MNP-Seq to reveal the ubiquitous, albeit subtle and neglected, genetic heterogeneities in homonyms of Nipponbare rice, a popular model organism for plant biology. This result raised a question on the consistency of the published results using the model plant. We also used MNP-Seq to accurately and efficiently determine the identities of plant varieties, a key but difficult problem for the protection of plant intellectual property rights. While being applied to plants in the current study, the MNP marker and MNP-Seq are general and readily applicable to similar problems in animals and micro-organisms.

molecular biology↗

bioRxiv2020

Chidamide decreases c-MET mRNA methylation and in turn increases the sensitivity of non-small cell lung cancer to crizotinib

IntroductionCrizotinib is a kinase inhibitor targeting c-MET/ALK/ROS1 used as the first-line chemical for the treatment of non-small cell lung cancer (NSCLC) with ALK mutations. Although c-MET is frequently overexpressed in 35-72% of NSCLC, most NSCLCs are primarily resistant to crizotinib treatment. MethodA set of NSCLC cell lines were used to test the effect of chidamide on the crizotinib sensitivity in vitro and in vivo. Relationships between the synergistic effect of chidamide and c-MET expression and RNA methylation were systemically studied with a battery of molecular biological assays. ResultsWe found for the first time that chidamide could increase the crizotinib sensitivity of a set of ALK mutation-free NSCLC cell lines, especially those with high levels of c-MET expression. Notably, chidamide could not increase the crizotinib sensitivity of NSCLC cells cultured in serum-free medium without hepatocyte growth factor (HGF; a c-MET ligand). In contrast, the addition of HGF into the serum-/HGF-free medium could restore the synergistic effect of chidamide. Moreover, the synergistic effect of chidamide could also be abolished either by treatment with c-MET antibody or siRNA-knockdown of c-MET expression. While cells with low or no c-MET expression were primarily resistant to chidamide-crizotinib cotreatment, enforced c-MET overexpression could increase the sensitivity of these cells to chidamide-crizotinib cotreatment. Furthermore, chidamide could decrease c-MET expression by inhibiting mRNA N6-methyladenosine (m6A) modification through the downregulation of METTL3 and WTAP expression. Chidamide-crizotinib cotreatment significantly suppressed the activity of c-MET downstream molecules. Conclusionchidamide downregulated c-MET expression by decreasing its mRNA m6A methylation, subsequently increasing the crizotinib sensitivity of NSCLC cells in a c-MET-/HGF-dependent manner. GRAPHIC SUMMARY O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=126 SRC="FIGDIR/small/012971v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@5a81d4org.highwire.dtl.DTLVardef@19f1forg.highwire.dtl.DTLVardef@75d74forg.highwire.dtl.DTLVardef@8a9f77_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2019

Survey of severe fever with thrombocytopenia syndrome virus covert infection for healthy people in Henan Province, China

BackgroundSevere fever with thrombocytopenia syndrome (SFTS) is a severe emerging disease, and its incidence has been increasing in recent years. A cross-sectional study was conducted for healthy people in high SFTS endemic areas of Henan province in 2016. MethodsThis study used stratified random sampling method and finally 14 natural villages were selected as the investigation site. The questionnaire survey and serum collection were carried out from April to May in 2016. All the serum samples were detected by SFTSV IgM and IgG antibodies by ELISA. Only positive samples of SFTSV IgM antibody need be tested SFTSV RNA and virus cultured. A month after the specimen collection, all persons positive for IgM antibody were followed up one by one to confirm whether he or she was recessive infection. Results1463 healthy persons were investigated in total. The average seropositive rates of SFTS virus specific IgG and IgM antibodies were 10.46% (153/1463) and 0.82% (12/1463), respectively. IgM antibody was positive in 12 individuals, and 6 of them SFTS virus RNA were also detected. In addition, 5 SFTS virus were isolated from the 6 SFTS virus RNA (+) individuals. By genomic sequencing and phylogenetic analysis, 5 new isolates from healthy crowd all belonged to groups A, which were similar to other isolates from SFTS patients. After one month, all people with SFTS virus IgM antibody had no illness or symptoms. ConclusionsThis study confirmed there is SFTS recessive infection in human, and it is the first report about SFTS virus isolation in healthy people. Author SummarySevere fever with thrombocytopenia syndrome (SFTS), a severe emerging infectious disease, was discovered in rural areas of China. The first SFTS case was found in Henan province, which has had the largest number of SFTS cases in China every year since the disease was discovered. However, as a high incidence area of SFTS in Henan province, the serum prevalence rate of the virus in healthy people is still not clear. Therefore, a cross-sectional survey was performed in high endemic areas and epidemic seasons in 2016. The results showed that the level of specific SFTS seroprevlence was relatively higher and possibility increasing. SFTS RNA were positive and SFTS virus was isolated from the specimens of healthy people. This study confirmed there is SFTS recessive infection in human, and it is the first report about SFTS virus isolation in healthy people.

epidemiology↗