The Card19 locus of murine chromosome 13 regulates terminal cell lysis downstream of caspase activation and Gasdermin-D cleavage

Cell death plays a critical role in inflammatory responses. During pyroptosis, inflammatory caspases cleave Gasdermin D (GSDMD) to release an N-terminal fragment that generates plasma membrane pores that mediate cell lysis and IL-1 cytokine release. Terminal cell lysis and IL-1β release following caspase activation can be uncoupled in certain cell types or in response to particular stimuli, a state termed hyperactivation. However, the factors and mechanisms that regulate terminal cell lysis downstream of GSDMD cleavage remain poorly understood. In the course of studies to define regulation of pyroptosis during Yersinia infection, we identified a line of Card19-/- mice whose macrophages were protected from cell death and showed reduced pore formation during apoptosis or pyroptosis, yet had wild-type levels of caspase activation, IL-1 secretion, and GSDMD cleavage. Unexpectedly, CARD19, a mitochondrial CARD-containing protein, was not directly responsible for this, as two independently-generated CRISPR/Cas9 Card19 knockout mice showed no defect in macrophage cell lysis. The original Card19-/- line was generated in a 129SvEvBrd background, and SNP analysis revealed a six megabase region of 129 origin co-segregating with the Card19 locus. Card19 is located on chromosome 13, adjacent to Ninj1, which was recently reported to regulate cell lysis downstream of GSDMD activation. Nonetheless, we could not detect major defects in NINJ1 protein expression or mutations in Ninj1 coding sequence in Card19-/- mice. Mice from the original Card19-/- line exhibited significantly increased susceptibility to Yersinia infection, demonstrating that cell lysis itself plays a key role in protection against bacterial infection. Our findings identify a locus on murine chromosome 13 that regulates the ability of macrophages to undergo plasma membrane rupture downstream of gasdermin cleavage, and implicates additional NINJ1-independent factors that control terminal cell lysis.

Detection of Zoonotic Yersinia Infection in Symptomatic and Asymptomatic Dogs in Sokoto State Nigeria

Background: Zoonotic Yersinia infection has been previously reported in humans and animal hosts in Nigeria, occasionally with fulminant disease. Despite earlier evidence of Yersinia pathogen circulating in human and animal populations in Nigeria, studies and suspicion index to Yersinia is below an acceptable average amongst clinicians, diagnosticians, academics and health policy officers. Methods: The deoxycholate Citrate Agar (DCA) was used as a selective media to culture Yersinia, preceded by inoculation in MacConkay agar. Plates with evident growth in the differential media consistent with reported accounts for Yersinia were picked and inoculated in selective medium and left for 48 hours until growth was seen, other samples were left until five days before being discarded as negative. Pure cultures were subjected to a comprehensive biochemical test standard and previously applied for diagnosis and discrimination of Yersinia species. Result: This research recorded an overall microbial prevalence of 30%. Prevalence of Yersinia enterocolitica was 18.3% and Y. pseudotuberculosis 11.7%. Male dogs presented a relative prevalence of Y. enterocolitica 40.9% compared with 59.1% recorded for female dogs. Symptomatic dogs presented a relative prevalence of Y. enterocolitica of 86.4% and Y. pseudotuberculosis of 71.4%

Detection of Zoonotic Yersinia Infection in Symptomatic and Asymptomatic Dogs in Sokoto State Nigeria

Background: Zoonotic Yersinia infection has been previously reported in humans and animal hosts in Nigeria, occasionally with fulminant disease. Despite earlier evidence of Yersinia pathogen circulating in human and animal populations in Nigeria, studies and suspicion index to Yersinia is below an acceptable average amongst clinicians, diagnosticians, academics and health policy officers. Methods: The Deoxycholate Citrate Agar (DCA) was used as selective media to culture Yersinia preceded by inoculation in MacConkay agar. Plates with evident growth in the differential media consistent with reported accounts for Yersinia were picked and inoculated in selective medium and left for 48 hours until growth was seen, other samples left until five days before being discarded as negative. Pure cultures were subjected to comprehensive biochemical tests standard and previously applied for diagnosis and discrimination of Yersinia species. Result: This research recorded an overall microbial prevalence of 30%. Prevalence of Yersinia enterocolitica was 18.3% and Y. pseudotuberculosis 11.7%. Male dogs presented a relative prevalence of Y.

Clinical signs in dogs attributed to Yersinia enterocolitica antigen 0:9

Canine yersiniosis is currently a scantily researched disease. Two agents predominately cause yersiniosis: Y. enterocolitica (gut yersiniosis), Y. preudotuberculosis (yersiniosis). There are three clinical forms of the disease: intestinal, generalized and secondary-focal. Current available research states the prevalence of Y. enterocolitica against other biovariants in canine infections. The majority of infected dogs demonstrate both asymptomatic clinical course and unspecific symptoms or serve as a carrier. Meanwhile yersiniosis pose a threat to human health causing a severe complex of symptoms. In some cases the disease can be lethal, thus the disease has both epizootological and epidemiological value. The goal of this paper was to generalize clinical signs in dogs that demonstrated positive reaction to Y. enterocolitica antigen 0:9, which is a dominant causative agent of yersiniosis in the northeastern region of Ukraine. The study was conducted based on clinical data, biochemical and hematological laboratory studies. Contamination of canine subjects with Y. enterocolitica 0:9 was conducted using agglutination reaction using respective antigen. The research showed, that the dominant symptoms in canines, affected by Yersinia serovariant 0:9 were gastrointestinal lesions in 100 % of the cases. The clinical signs included melena or bloody stool, general depression, anorexia, cachexia, more rarely – vomiting, tachypnea and breathing irregularities. The results of biochemical blood assays and CBC were heterogeneous and cannot be used as a specific marker of Yersinia infection. The main method of confirmation for Yersinia infection would be a serological agglutination reaction, which can identify positive diagnostic titers in animal blood samples. Further research is planned to study mono- and concurrent course of Yersiniosis with different infectious diseases.