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Nagel, Z.

Publications and source records attributed to Nagel, Z..

2 recordsLinked to original sources

Chlamydia coinfection inhibits HPV-induced safeguards of the cellular and genomic integrity in patient-derived ectocervical organoids

Cervical mucosa is continually confronted by coinfections with pathogenic microbes. In addition to human papillomavirus, coinfections with Chlamydia trachomatis have been associated with an increased risk of cervical cancer. However, the dynamics of coinfections, their impact on the epithelia, and their contribution to pathogenesis remain obscure. Using a novel human ectocervical squamous stratified epithelial organoids, we recapitulated the natural infections of the cervix by Chlamydia, HPV, and their coinfections. Towards this, we genetically manipulated the healthy organoids to mimic in vivo HPV persistence by introducing E6E7 oncogenes into the host genome. HPV persistent organoids show enhanced tissue regeneration, increased proliferation and differentiation of stem cells, and nuclear atypia resembling cervical intraepithelial neoplasia grade 1. We found that HPV interferes with normal Chlamydia development. Further, a unique transcriptional host response induced by Chlamydia and HPV leads to distinct reprogramming of host cell processes. Strikingly, in coinfections, Chlamydia impedes HPV-induced mechanisms that maintain cellular and genome integrity, including mismatch repair (MMR). Distinct post-translational proteasomal-degradation and E2F-mediated transcriptional regulation delineate the inverse regulation of MMR during coinfections. Our study employing organoids demonstrates the jeopardy of multiple sequential infection processes and the unique cellular microenvironment they create, accelerating neoplastic progression.

cancer biology↗

Paradoxical role of AT-rich interactive domain 1A in restraining pancreatic carcinogenesis

Background & AimsARID1A is postulated to be a tumor suppressor gene owing to loss-of-function mutations in human pancreatic ductal adenocarcinomas (PDAC). However, its role in pancreatic pathogenesis is not clear despite recent studies using genetically engineered mouse (GEM) models. We aimed at further understanding of its direct functional role in PDAC, using a combination of GEM model, PDAC cell lines. MethodsPancreas-specific mutant Arid1a-driven GEM model (Ptf1a-Cre;KrasG12D;Arid1af/f or "KAC") was generated by crossing Ptf1a-Cre;KrasG12D ("KC") mice with Arid1af/f mice and characterized histologically with timed necropsies. Arid1a was also deleted using CRISPR-Cas9 system in established PDAC cell lines to study the immediate effects of Arid1a loss in isogenic models. Cells lines with or without Arid1a expression were developed from respective autochthonous PDAC GEM models, compared functionally using various culture assays, and subjected to RNA-sequencing for comparative gene expression analysis. DNA damage repair was analyzed in cultured cells using immunofluorescence and COMET assay. ResultsArid1a is critical for early progression of mutant Kras-driven pre-malignant lesions into PDAC, as evident by lower Ki-67 and higher apoptosis staining in "KAC" as compared to "KC" mice. Enforced deletion of Arid1a in established PDAC cell lines caused suppression of cellular growth and migration, accompanied by compromised DNA damage repair. Despite early development of relatively indolent cystic precursor lesions called intraductal papillary mucinous neoplasms (IPMNs), a subset of "KAC" mice developed aggressive PDAC in later ages. PDAC cells obtained from older autochthonous "KAC" mice revealed epigenetic changes underlying the various compensatory mechanisms to overcome the growth suppressive effects of Arid1a loss. ConclusionsArid1a is an essential survival gene whose loss impairs cellular growth, and thus, its expression is critical during early stages of pancreatic tumorigenesis in mouse models.

cancer biology↗