Biology subjects

Beiting, D. P.

Publications and source records attributed to Beiting, D. P..

At least 19 recordsLinked to original sources

bioRxiv2026

Ablation of a maternal Cryptosporidium mRNA-binding protein results in sterile sporozoites

Infection with Cryptosporidium is a leading cause of diarrheal disease and early childhood mortality. This apicomplexan parasite undergoes asexual and sexual replication within the same host and recent studies have shown an intrinsic developmental program of obligate transition to male and female gametes and sex. While factors were identified that control male fate and development, how female gene expression is orchestrated remains largely unknown. Here we use the Cryptosporidium Single Cell Atlas to discover an RNA binding protein (F-RBP) as one of the earliest markers of female identity. Reporter parasites engineered based on this gene allowed us to calibrate transcriptional pseudotime against the real time of female development revealing a significant window of transcriptional fate ambiguity. While F-RBP is an early transcript, the protein persists throughout female development and into the zygote. Conditional ablation of the F-RBP gene showed it to be dispensable for sex determination and early female development in vitro. However, the gene is essential in vivo and its loss results in rapid cure. Cell biological experiments link this loss to the production of sterile oocysts which release sporozoites incapable of host cell invasion. F-RBP binds transcripts highly expressed in the female gamete enriched for a YBOX primary sequence motif and forms mRNA protein complexes in late females akin to processing or P bodies. We propose F-RBPs essential role to be in the regulation of long-term homeostasis of maternally inherited RNA required for sporozoite infectivity.

microbiology↗

bioRxiv2026

SPTBN2 promotes an immunosuppressive tumor microenvironment and cross-resistance to anti-cancer therapies

Immunosuppressive tumor microenvironment (TME) inactivates CD8+ cytotoxic lymphocytes (CTLs). Here, we identify SPTBN2 spectrin as a key immunosuppressive regulator induced in CTLs in response to nutritional deficit. In human pancreatic and colorectal cancers, SPTBN2 expression negatively correlated with CTL infiltration and patients survival. In TME of mouse pancreatic and colorectal adenocarcinomas, SPTBN2 inactivated intratumoral CTLs, stimulated tumor growth and conferred cross-resistance to anti-cancer therapies. SPTBN2 knockout protected CAR T-cells from trogocytosis and increased their memory state. SPTBN2 maintained levels of cell surface proteins such as BTLA that undermine CAR T-cell cytotoxicity and promote exhaustion. Re-expression of BTLA largely reversed phenotypes in SPTBN2-deficient CAR T-cells. In manufactured CAR T cells, SPTBN2 was associated with their clinical failure in pediatric patients with leukemia. Accordingly, ablation of SPTBN2 in CAR T-cells increased their cytotoxicity, in vivo persistence and therapeutic effects indicating that SPTBN2 can be targeted to increase the efficacy of anti-cancer therapies.

cancer biology↗

bioRxiv2025

Diverse infections transcriptionally reprogram the intestinal epithelium and epithelial-immune cell interactions

The distal small intestine plays vital roles in host physiology by regulating nutrient and fluid homeostasis. Despite being impacted in Crohns disease and a major target for a range of infections, we know relatively little about the complexity of cellular responses and cell-cell communication in the ileum during infection. Single cell and spatial transcriptomics have emerged as powerful technologies to study tissue heterogeneity in the gut, but these tools have focused on the large intestine, in part due to the accessibility of this tissue for biopsies and its importance in cancer. Here we present GutPath, an atlas of over 500,000 single cells with RNA and protein expression profiles for 91 cell states in the ileum across diverse infectious archetypes. We show that GutPath accurately captures established immune responses to infection while revealing pathogen-specific responses in enterocytes. To highlight the discovery potential of this atlas, we identify a novel enterocyte cell state present during Yersinia pseudotuberculosis infection that is spatially linked to bacterial load and tissue pathology. GutPath establishes a much-needed resource for the immunology community that will accelerate the study of the transcriptional diversity of cellular landscapes in the small intestine.

immunology↗

bioRxiv2025

Widespread genomic heterogeneity at the type II NAD(P)H dehydrogenase locus predisposes Cryptosporidium to clofazimine resistance

The parasite Cryptosporidium is a leading cause of life-threatening diarrheal disease, and effective treatment is not available. The discovery of potent anti-Cryptosporidium activity of clofazimine, offered the opportunity to repurpose a drug already used to treat leprosy and tuberculosis. However, clofazimine failed in a human trial, which was attributed to poor bioavailability. Here, we observed differential susceptibility among parasite isolates which we exploit to map the mode of action to type II NADH dehydrogenase (NDH2) in an unbiased genetic cross. Targeted genetic ablation of NDH2 resulted in profound clofazimine resistance, and biochemical studies demonstrated NDH2 mediated electron transfer to clofazimine. Through genomic analyses we uncovered heterogeneity at the NDH2 locus for C. parvum and C. hominis and widespread carriage of a conserved attenuated allele across multiple continents. This heterogeneity allows parasites genomically linked through frequent sexual recombination to adjust to changing NDH2 requirements and predisposes Cryptosporidium to evade clofazimine treatment.

microbiology↗

bioRxiv2025

Human wastewater contamination drives the emergence of novel multidrug resistant bacteria in the Galapagos marine ecosystem.

Since the publication of Charles Darwins On the Origin of Species in 1859, the Galapagos archipelago has become emblematic of natural selection and evolution. While the lens of evolution in the Galapagos has traditionally focused on iconic megafauna, including finches, marine iguanas, and giant tortoises, the marine environment is also home to diverse microbial ecosystems that are constantly evolving under selective pressure from environmental factors such as human activity. We focused on the second most populated island within the archipelago -- San Cristobal -- an island that has experienced rapid urbanization and intense international tourism pressure. Using a lab-free approach, we spatiotemporally mapped wastewater contamination around San Cristobal. On-site metagenomic sequencing revealed a stark shift in genera and a higher count of antimicrobial resistance genes at wastewater-associated sites. Over 40% of lactose-fermenting Enterobacteriaceae isolates collected from sewage and wastewater outfall exhibited multidrug resistance (MDR). Long-read sequencing and de novo assembly of bacterial genomes and plasmids from MDR Escherichia coli revealed frequent and rapid reassortment of antimicrobial resistance genes on plasmids, generating unique antimicrobial resistance profiles. This study not only provides a framework for conducting antimicrobial resistance research in low-resource settings but also underscores the impact of wastewater contamination on the environmental AMR landscape and highlights potential threats to human and animal health.

microbiology↗

bioRxiv2025

Genetic crosses reveal genomic loci responsible for virulence in Cryptosporidium parvum infection

The relationship between parasite genotype and pathogenesis is largely unknown for Cryptosporidium, a leading cause of diarrheal disease in children. An array of parasites with similar genomes produces varied disease outcomes in different hosts. Here, we isolate and characterize Cryptosporidium parvum strains that show marked differences in virulence and persistence in mice. Taking advantage of the sexual lifecycle of this eukaryotic pathogen, we use genetic crosses to discover the underlying chromosomal loci. Whole-genome sequencing and bulk segregant analysis of infection selected progeny mapped three loci on chromosomes 2, 6, and 7 associated with the ability to colonize and persist in mice and the positions of drug resistance genes. The chromosome 6 locus encodes the hyper-polymorphic surface glycoprotein GP60. Reverse genetic studies in both parental strains demonstrate that GP60 controls parasite burden and virulence, but not persistence, and reveal the dominance of the less virulent allele, suggesting it restricts virulence.

genetics↗

bioRxiv2025

A Wildlife Health Outbreak Response Table-top Exercise for Pandemic Preparedness Planning

Zoonotic diseases have received significantly more attention over the last few decades, emerging with increasing frequency and causing the majority of notable disease outbreaks in this century, including the COVID-19 pandemic. As human activities and shifting climate patterns induce changes in the environment that alter habitat and range of reservoir species, the potential for human and animal interactions will increase and enhance the opportunity for spillover. Thus, any emergency response preparedness planning must take into account the function and coordination of agencies across the sectors of human, animal and environmental health. Within the Commonwealth of Pennsylvania a table-top exercise was performed to evaluate a multi-agency response during a hypothetical zoonotic disease investigation. The exercise was evaluated by the participants to gain feedback on the overall process and lessons learned. Here, we describe the tabletop exercise scenario and the insights gained. We found that differences in operational structure create challenges for interdepartmental communication and in the ability to resource a coordinated response, highlighting opportunities to develop infrastructure that will facilitate future actions. A set of recommendations are outlined that may enhance cross-agency activities and promote more effective and efficient emergency response.

scientific communication and education↗

bioRxiv2025

Defining neuronal responses to the neurotropic parasite Toxoplasma gondii

A select group of pathogens infect neurons in the brain. Prior dogma held that neurons were "defenseless" against infecting microbes, but many studies suggest that neurons can mount anti-microbial defenses. However, a knowledge gap in understanding how neurons respond in vitro and in vivo to different classes of micro-organisms remains. To address this gap, we compared a transcriptional dataset derived from primary neuron cultures (PNCs) infected with the neurotropic intracellular parasite Toxoplasma gondii with a dataset derived from neurons injected with T. gondii protein in vivo. These curated responses were then compared to the transcriptional responses of PNCs infected with the single stranded RNA viruses West Nile Virus (WNV) or Zika Virus (ZKV). These analyses highlighted a conserved response to infection associated with chemokines (Cxcl10, Ccl2) and cytokines (interferon signaling). However, T. gondii had diminished IFN- signaling in vitro compared to the viral datasets and was uniquely associated with a decrease in neuron-specific genes (Snap25, Slc17a7, Prkcg). These data underscore that neurons participate in infection-induced neuroinflammation and illustrate that neurons possess both pathogen-specific and pathogen-conserved responses. ImportanceThough neurons are commonly the target of pathogens that infect the CNS, few datasets assess the neuronal response to infection. This paucity of data is likely because neurons are perceived to have diminished immune capabilities. However, to understand the role of neurons in neuroinflammation and their immune capabilities, their responses must be investigated. Here we analyzed publicly accessible, neuron-specific datasets to compare neuron responses to a eukaryotic pathogen versus two Orthoflaviviruses. A better understanding of neuron responses to different infections will allow us to develop methods for inhibiting pathways that lead to neuron dysfunction, enhancing those that limit pathogen survival, and mitigating infection-induced damage to the CNS.

microbiology↗

bioRxiv2025

Short-term alterations in dietary amino acids override host genetic susceptibility and reveal mechanisms of Salmonella Typhimurium small intestine colonization

In addition to individual genetics, environmental factors (e.g., dietary changes) may influence host susceptibility to gastrointestinal infection through unknown mechanisms. Herein, we developed a model in which CBA/J mice, a genetically resistant strain that tolerates intestinal colonization by the enteric pathogen Salmonella Typhimurium (S. Tm), rapidly succumb to infection after exposure to a diet rich in L-amino acids (AA). In mice, S. Tm-gastroenteritis is restricted to the large intestine (cecum), limiting their use to understand S. Tm small intestine (ileum) colonization, a feature of human Salmonellosis. Surprisingly, CBA mice fed AA diet developed ileitis with enhanced S. Tm ileal colonization. Using germ-free mice and ileal-fecal slurry transplant, we found diet-mediated S. Tm ileal expansion to be microbiota-dependent. Mechanistically, S. Tm relied on Fructosyl-asparagine utilization to expand in the ileum during infection. We demonstrate how AA diet overrides host genetics by altering the gut microbiotas ability to prevent S. Tm ileal colonization.

microbiology↗

bioRxiv2024

NF-κB Signaling is Required for X-Chromosome Inactivation Maintenance Following T cell Activation

X Chromosome Inactivation (XCI) is a female-specific process which balances X-linked gene dosage between sexes. Unstimulated T cells lack cytological enrichment of Xist RNA and heterochromatic modifications on the inactive X chromosome (Xi), and these modifications become enriched at the Xi after cell stimulation. Here, we examined allele-specific gene expression and the epigenomic profiles of the Xi following T cell stimulation. We found that the Xi in unstimulated T cells is largely dosage compensated and is enriched with the repressive H3K27me3 modification, but not the H2AK119-ubiquitin (Ub) mark, even at promoters of XCI escape genes. Upon CD3/CD28-mediated T cell stimulation, the Xi accumulates H2AK119-Ub and H3K27me3 across the Xi. Next, we examined the T cell signaling pathways responsible for Xist RNA localization to the Xi and found that T cell receptor (TCR) engagement, specifically NF-{kappa}B signaling downstream of TCR, is required. Disruption of NF-{kappa}B signaling, using inhibitors or genetic deletions, in mice and patients with immunodeficiencies prevents Xist/XIST RNA accumulation at the Xi and alters expression of some X-linked genes. Our findings reveal a novel connection between NF-{kappa}B signaling pathways which impact XCI maintenance in female T cells.

immunology↗

bioRxiv2022

Genetic ablation of a female specific Apetala 2 transcription factor blocks oocyst shedding in Cryptosporidium parvum

The apicomplexan parasite Cryptosporidium is a leading global cause of diarrheal disease, and the infection poses a particularly grave threat to young children and those with weakened immune function. Infection occurs by ingestion of meiotic spores called oocysts, and transmission relies on fecal shedding of new oocysts. The entire lifecycle thus occurs in a single host and features asexual as well as sexual forms of replication. Here we identify and locus tag two Apetala 2-type (AP2) transcription factors and demonstrate that they are exclusively expressed in male and female gametes, respectively. To enable functional studies of essential genes in C. parvum we develop and validate a small molecule inducible gene excision system, which we apply to the female factor AP2-F to achieve conditional gene knock out. Analyzing this mutant, we find the factor to be dispensable for asexual growth and early female fate determination in vitro, but to be required for oocyst shedding in infected animals in vivo. Transcriptional analyses conducted in the presence or absence of AP2-F revealed that the factor controls the transcription of genes encoding crystalloid body proteins, which are exclusively expressed in female gametes. In C. parvum, the organelle is restricted to sporozoites, and its loss in other apicomplexan parasites leads to blocked transmission. Overall, our development of conditional gene ablation in C. parvum provides a robust method for genetic analysis in this parasite that enabled us to identify AP2-F as an essential regulator of transcription required for oocyst shedding and transmission.

microbiology↗

bioRxiv2022

Improved eukaryotic detection compatible with large-scale automated analysis of metagenomes

BackgroundEukaryotes such as fungi and protists frequently accompany bacteria and archaea in microbial communities. Unfortunately, their presence is difficult to study with shotgun metagenomic sequencing since prokaryotic signals dominate in most environments. Recent methods for eukaryotic detection use eukaryote-specific marker genes, but they do not incorporate strategies to handle the presence of eukaryotes that are not represented in the reference marker gene set, and they are not compatible with web-based tools for downstream analysis. ResultsHere we present CORRAL (for Clustering{square}Of{square}Related Reference ALignments), a tool for identification of eukaryotes in shotgun metagenomic data based on alignments to eukaryote-specific marker genes and Markov clustering. Using a combination of simulated datasets, mock community standards, and large publicly available human microbiome studies, we demonstrate that our method is not only sensitive and accurate but is also capable of inferring the presence of eukaryotes notincluded in the marker gene reference, such as novel strains. Finally, we deploy CORRAL on our MicrobiomeDB.org resource, producing an atlas of eukaryotes present in various environments of the human body and linking their presence to study covariates. ConclusionsCORRAL allows eukaryotic detection to be automated and carried out at scale. Implementation of CORRAL in MicrobiomeDB.org creates a running atlas of microbial eukaryotes in metagenomic studies. Since our approach is independent of the reference used, it may be applicable to other contexts where shotgun metagenomic reads are matched against redundant but non-exhaustive databases, such as identification of bacterial virulence genes or taxonomic classification of viral reads.

bioinformatics↗

bioRxiv2022

Inflammatory monocytes promote pyogranuloma formation to counteract Yersinia blockade of host defense

Granulomas are organized immune cell aggregates that form in response to chronic infection or antigen persistence. Yersinia pseudotuberculosis (Yp) blocks innate inflammatory signaling and phagocytosis, inducing formation of neutrophil-rich pyogranulomas within lymphoid tissues. Here, we uncover that Yp triggers pyogranuloma formation within the murine intestinal mucosa, a site not known to contain such structures. Mice lacking circulating monocytes fail to form defined pyogranulomas, have defects in neutrophil activation, and succumb to Yp infection. Yersinia lacking the virulence factors that block phagocytosis did not induce pyogranulomas, indicating that intestinal pyogranulomas form in response to Yp disruption of phagocytosis. Notably, mutation of a single anti-phagocytic virulence factor, YopH, restored pyogranuloma formation and control of Yp infection in monocyte-deficient mice, demonstrating that monocytes override YopH-dependent blockade of innate immune defense. This work reveals an unappreciated site of Yersinia intestinal invasion, and defines host and pathogen drivers of intestinal granuloma formation.

microbiology↗

bioRxiv2022

Impact of secondary TCR engagement on the heterogeneity of pathogen-specific CD8+ T cell response during acute and chronic toxoplasmosis

Initial TCR engagement of CD8+ T cells results in T cell expansion, and these early events influence the generation of diverse effector and memory populations. During infection, some activated T cells re-encounter cognate antigen, but how these events influence local effector responses or formation of memory populations is unclear. To address this issue, OT-I T cells which express the Nur77-GFP reporter of TCR activation were paired with T. gondii that express OVA to assess the impact of TCR activation on CD8+ T cell responses. During acute infection, TCR stimulation in affected tissues correlated with parasite burden and was associated with markers of effector cells while Nur77-GFP- OT-I showed signs of effector memory potential. However, adoptive transfer of Nur77-GFP negative or positive OT-I from infected mice into naive recipients resulted in formation of similar memory populations. During the chronic stage of infection in the CNS, TCR activation was associated with large scale transcriptional changes and the acquisition of an effector T cell phenotype as well as the generation of a population of CD103+ CD69+ Trm like cells. However, while inhibition of parasite replication resulted in reduced effector responses it did not alter the Trm population. These data sets highlight the contribution of recent TCR activation on the phenotypic heterogeneity of the CD8+ T cell response but suggest that this process has a limited impact on memory populations at acute and chronic stages of infection. Author SummaryCD8+ T cells are important to control many acute and chronic infections, however the role that recent T cell receptor stimulation plays in the formation of ongoing T cell responses is unclear. Here, we utilize a genetic reporter of TCR stimulation and high parameter flow cytometry to characterize TCR-driven phenotypes of pathogen specific T cell responses to the parasite Toxoplasma gondii during acute and chronic infection in the periphery and central nervous system. This work demonstrates the importance of recent TCR stimulation in driving local effector CD8+ T cell responses in peripheral tissues during infection, as well as the plasticity of the formation of memory T cells. Additionally, we utilize static and live imaging to investigate how Toxoplasma gondii life cycle impacts the ability to present antigen to CD8+ T cells. These studies aid in our understanding of how effector and memory CD8+ T cell responses are generated and maintained during an infection.

immunology↗

bioRxiv2021

A genetic screen identifies a protective type III interferon response to Cryptosporidium that requires TLR3 dependent recognition

Cryptosporidium is a leading cause of severe diarrhea and diarrheal-related death in children worldwide. As an obligate intracellular parasite, Cryptosporidium relies on intestinal epithelial cells to provide a niche for its growth and survival, but little is known about the contributions that the infected cell makes to this relationship. Here we conducted a genome wide CRISPR/Cas9 knockout screen to discover host genes required for Cryptosporidium parvum infection and/or host cell survival. Gene enrichment analysis indicated that the host interferon response, glycosaminoglycan (GAG) and glycosylphosphatidylinositol (GPI) anchor biosynthesis are important determinants of susceptibility to C. parvum infection. Several of these pathways are linked to parasite attachment and invasion and C-type lectins on the surface of the parasite. Evaluation of transcript and protein induction of innate interferons revealed a pronounced type III interferon response to Cryptosporidium in human cells as well as in mice. Treatment of mice with IFN{lambda} reduced infection burden and protected immunocompromised mice from severe outcomes including death, with effects that required STAT1 signaling in the enterocyte. Initiation of this type III interferon response was dependent on sustained intracellular growth and mediated by the pattern recognition receptor TLR3. We conclude that host cell intrinsic recognition of Cryptosporidium results in IFN{lambda} production critical to early protection against this infection. Author SummaryCryptosporidium infection is an important contributor to global childhood mortality. There are currently no vaccines available, and the only drug has limited efficacy in immunocompromised individuals and malnourished children who need it most. To discover which host proteins are essential for Cryptosporidium infection, we conducted a genome wide knockout screen in human host cells. Our results confirm the importance of glycosaminoglycans on the surface of epithelial cells for attachment and invasion of the parasite. We also found that host GPI anchor biosynthesis and interferon signaling pathways were enriched by our screen. Examining the role of interferon signaling further we found a type III interferon response, IFN{lambda}, was generated in response to infection and shown to be initiated in the infected cell. Utilizing mouse models of infection, we found that the type III interferon response was important early during infection with its induction likely preceding IFN{gamma}, a key cytokine for the control of this infection. We also determined that TLR3 was the pattern recognition receptor responsible for IFN{lambda} production during Cryptosporidium infection. Our work shows that IFN{lambda} acts directly on the enterocyte and its use in treating immunocompromised mice produced striking reductions in infection.

microbiology↗

bioRxiv2021

Gut microbiota features associated with Clostridioides difficile colonization in dairy calves

Diarrheal disease, a major cause of morbidity and mortality in dairy calves, is strongly associated with the health and composition of the gut microbiome. Clostridioides difficile is an opportunistic pathogen that proliferates and can produce enterotoxins when the host experiences gut dysbiosis. However, even asymptomatic colonization with C. difficile can be associated with differing degrees of microbiome disruption in a range of species, including people, swine, and dogs. Little is known about the interaction between C. difficile and the gut microbiome in dairy calves. In this study, we sought to define microbial features associated with C. difficile colonization in pre-weaned dairy calves less than 2 weeks of age. We characterized the fecal microbiota of 80 calves from 23 different farms using 16S rRNA sequencing and compared the microbiota of C. difficile-positive (n=24) and C. difficile-negative calves (n=56). Farm appeared to be the greatest source of variability in the gut microbiota. When controlling for calf age, diet, and farm location, there was no significant difference in Shannon alpha diversity (P= 0.50) or in weighted UniFrac beta diversity (P=0.19) between C. difficile-positive and -negative calves. However, there was a significant difference in beta diversity as assessed using Bray-Curtiss diversity (P=0.0077), and C. difficile-positive calves had significantly increased levels of Ruminococcus (gnavus group) (Adj. P=0.052), Lachnoclostridium (Adj. P=0.060), Butyricicoccus (Adj. P=0.060), and Clostridium sensu stricto 2 compared to C. difficile-negative calves. Additionally, C. difficile-positive calves had fewer microbial co-occurrences than C. difficile-negative calves, indicating reduced bacterial synergies. Thus, while C. difficile colonization alone is not associated with dysbiosis and is therefore unlikely to result in an increased likelihood of diarrhea in dairy calves, it may be associated with a more disrupted microbiota.

microbiology↗

bioRxiv2021

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-1{beta} 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-deficient mice (Card19lxcn) whose macrophages were protected from cell lysis and showed reduced apoptosis and 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, and expression of CARD19 in Card19lxcn macrophages did not restore cell lysis. Card19 is located on chromosome 13, adjacent to Ninj1, which was recently reported to regulate cell lysis downstream of GSDMD activation. Intriguingly, RNA-seq and western blotting revealed that Card19lxcn BMDMs are hypomorphic for NINJ1 expression, and reconstitution of Ninj1 in Card19lxcn immortalized BMDMs restored cell lysis. Card19lxcn mice exhibited significantly increased susceptibility to Yersinia infection, demonstrating that cell lysis itself plays a key role in protection against bacterial infection. Our findings identify genetic targeting of Card19 being responsible for off-target effects on the adjacent Ninj1 gene, thereby disrupting the ability of macrophages to undergo plasma membrane rupture downstream of gasdermin cleavage and impacting host survival and bacterial control during Yersinia infection. Author SummaryProgrammed cell death is critical for regulating tissue homeostasis and host defense against infection. Pyroptosis is an inflammatory form of programmed cell death that couples cell lysis with release of inflammatory cytokines. Cell lysis is triggered by activation of particular intracellular pore forming proteins, but how regulation of cell lysis occurs is not well understood. Genetic targeting of Card19 on chromosome 13 resulted in decreased expression of the adjacent gene, Ninj1 which was recently found to regulate terminal lysis events in response to cell death-inducing stimuli. We found that macrophages from Card19-deficient mice were resistant to multiple forms of cell death in response to a variety of inflammatory stimuli, including canonical and non-canonical inflammasome activation, as well as triggers of cell-extrinsic apoptosis. Notably, Card19-deficient mice were more susceptible to Yersinia infection, indicating that cell lysis contributes to control of bacterial infections. Our data provide new insight into the impact of terminal cell lysis on control of bacterial infection and highlight the role of additional factors that regulate lytic cell death downstream of gasdermin cleavage.

immunology↗

bioRxiv2021

Crosstalk between enterocytes and innate lymphoid cells drives early IFN-g-mediated control of Cryptosporidium

The intestinal parasite, Cryptosporidium, is a major contributor to global child mortality and causes opportunistic infection in immune deficient individuals. Innate resistance to Cryptosporidium, which specifically invades enterocytes, is dependent on the production of IFN-{gamma}, yet whether enterocytes contribute to parasite control is poorly understood. In this study, utilizing the natural mouse pathogen, Cryptosporidium tyzzeri, we show that epithelial-derived IL-18 synergized with IL-12 to stimulate innate lymphoid cell (ILC) production of IFN-{gamma}. This innate IFN-{gamma} was required for early parasite control. Loss of STAT1 in enterocytes, but not dendritic cells or macrophages, antagonized early parasite control. Transcriptional profiling of enterocytes from infected mice identified an IFN-{gamma} signature and enrichment of anti-microbial effectors like IDO, GBP and IRG. Deletion experiments identified a role for Irgm1/m3 in parasite control. Thus, enterocytes promote ILC production of IFN-{gamma} that acts on enterocytes to restrict the growth of C. tyzzeri.

immunology↗