Biology subjects

Orozco, R. C.

Publications and source records attributed to Orozco, R. C..

8 recordsLinked to original sources

bioRxiv2025

An autoimmunity-associated allele of PTPN22 enhances the innate immune response to promote protection against acute coronavirus infection

Allelic variation can impact viral clearance and disease severity. Still, our understanding of the effect of the autoimmunity-associated allelic variant of Ptpn22 (PEP-R619W) on antiviral immunity remains incomplete, as previous reports have only focused on chronic Lymphocytic Choriomeningitis virus (LCMV) infection. This research defines how the loss of Ptpn22 (PEP-null) and PEP-R619W changes antiviral immunity during an acute coronavirus infection. We address the hypothesis that CRISPR/Cas9-generated PEP-null and PEP-R619W mice have enhanced antiviral immunity over PEP-WT mice during coronavirus infection. Following Mouse Hepatitis Virus (MHV) A59 infection, we interrogated pathology, cytokine production, and cellular responses in the blood, spleen, and liver of PEP-WT, PEP-null, and PEP-R619W mice. Key findings show that PEP-R619W mice have reduced viral titer and weight loss, increased survival, and more mature natural killer (NK) cells in the liver and spleen compared to PEP-WT mice. Interestingly, protection against disease in PEP-null mice was inoculation-dose-dependent, whereas PEP-R619W conferred immunity regardless of infection dose. Further, Rag1-/- PEP-R619W mice had increased survival and reduced viral titer over Rag1-/- PEP-WT mice. PEP-R619W mice also had higher concentrations of IFN{gamma} and enhanced IFN{gamma} production by mature NK cells in the liver at 3 days post-infection. Finally, NK cell depletion elevated PEP-R619W viral titer to similar levels as PEP-WT mice. This is one of the first studies investigating the role of Ptpn22 within NK cells and demonstrates that the Ptpn22 allelic variant augments NK cell function and is beneficial during coronavirus infection. Significance StatementApproximately 5-15% of the North American population has the PTPN22 1858C>T allele, which has been linked with numerous autoimmune diseases and is considered the highest non-HLA risk allele for autoimmunity. Due to this link, the PTPN22 1858C>T allele is often considered pathologic or detrimental. However, recent studies have demonstrated the benefit of this allele in protection from chronic virus infection and some cancers. Yet, a significant research gap remains in understanding how the PTPN22 1858C>T allele impacts the immune response during acute, moribund infections. Using mice that are homozygous for the equivalent, autoimmunity-associated allele in Ptpn22, we demonstrate that this allele uniquely augments innate immunity and enhances Natural Killer cell function to protect against coronavirus infection.

immunology↗

bioRxiv2025

Type I Interferon production in myeloid cells is regulated by factors independent of Ptpn22

The immune regulatory gene PTPN22 is expressed in all immune cells and encodes Lyp in humans and the ortholog PEP in mice. The PTPN22 alternative allele, 1858C>T, is expressed in 5-15% of the North American population and is strongly associated with the development of autoimmune disease while simultaneously capable of providing protection during virus infection and cancer. In murine models, significant progress has been made in elucidating the molecular mechanisms that PEP and its pro-autoimmune variant (PEP-R619W) modulate T cell function, yet their influence on non-T cell pathways, such as antigen presenting cell cytokine production, remains less defined. Previously, it was reported that PEP promotes type I interferon (IFN-I) production in dendritic cells (DCs) and macrophages following TLR4 stimulus. Here, we show that contrary to previous results, both PEP-WT and the PEP-R619W variant do not promote IFN-I production in DCs and macrophages following exposure to LPS, 3p-hpRNA, or coronavirus MHV A59. We attribute the prior findings to mouse strain-specific differences and conclude that factors independent of PEP may be regulating IFN-I production in these studies. We further show that PEP and its R619W variant distinctly modulate the production of TNF, IL-12 and IL-2 in DCs following LPS stimulus. Taken together, our results challenge the current understanding of the role of PEP during inflammation while providing new insight into how the PEP-R619W variant may alter myeloid cell function during disease.

immunology↗

bioRxiv2025

IFN-γ signaling is required for the efficient replication of murine hepatitis virus (MHV) strain JHM in the brains of infected mice.

Neurotropic viruses are a major public health concern as they can cause encephalitis and other severe brain diseases. Many of these viruses, including flaviviruses, herpesviruses, rhabdoviruses and alphaviruses enter the brain through the olfactory neuroepithelium (ONE) in the olfactory bulbs (OB). Due to the low percentage of encephalitis that occurs following these infections, its thought that the OBs have specialized innate immune responses to eliminate viruses. Murine hepatitis virus strain JHM (JHMV) is a model coronavirus that causes severe encephalitis in mice and can access the brain through olfactory sensory neurons. Weve shown that a JHMV Mac1-mutant virus, N1347A, has decreased replication and disease in the brains of mice. Here we further show that this virus replicates poorly in the OB. However, it is unknown which innate immune factors restrict N1347A replication in the OB. RNA seq analysis of infected olfactory bulbs showed that IFN{gamma} was upregulated in the OB while IFN-{beta} was barely detectable at 5 days post-infection. To determine if IFN-{gamma} restricts JHMV N1347A replication, we utilized IFN-{gamma} and IFN-{gamma} receptor (IFN-{gamma}R) knockout (KO) mice. Surprisingly we found that JHMV WT and N1347A replicated very poorly in the OB and whole brains of both IFN-{gamma} and IFN-{gamma}R KO mice following intranasal infection, though survival and weight loss were unaltered. Furthermore, we determined that microglia were the primary cells producing IFN-{gamma} during the early stages of this infection. We conclude that IFN-{gamma} is required for the efficient replication of JHMV in the brains of infected mice.

microbiology↗

bioRxiv2024

PARP14 is pro- and anti-viral host factor that promotes IFN production and affects the replication of multiple viruses

PARP14 is a 203 kDa multi-domain protein that is primarily known as an ADP-ribosyltransferase, and is involved in a variety of cellular functions including DNA damage, microglial activation, inflammation, and cancer progression. In addition, PARP14 is upregulated by interferon (IFN), indicating a role in the antiviral response. Furthermore, PARP14 has evolved under positive selection, again indicating that it is involved in host-pathogen conflict. We found that PARP14 is required for increased IFN-I production in response to coronavirus infection lacking ADP-ribosylhydrolase (ARH) activity and poly(I:C), however, whether it has direct antiviral function remains unclear. Here we demonstrate that the catalytic activity of PARP14 enhances IFN-{beta} and IFN-{lambda} responses and restricts ARH-deficient murine hepatitis virus (MHV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication. To determine if PARP14s antiviral functions extended beyond CoVs, we tested the ability of herpes simplex virus 1 (HSV-1), a DNA virus, vesicular stomatitis virus (VSV), a negative-sense RNA virus, and lymphocytic choriomeningitis virus (LCMV), an ambisense RNA virus, to infect A549 PARP14 knockout (KO) cells. While LCMV infection was unaffected, HSV-1 replication was increased in PARP14 KO cells and VSV replication was decreased. These results indicate that PARP14 restricts HSV-1 replication but enhances the replication of VSV. A PARP14 active site inhibitor had no impact on HSV-1 or VSV replication, indicating that its effect on these viruses was independent of its catalytic activity. These data demonstrate that PARP14 promotes IFN production and has both proviral and antiviral functions targeting multiple viruses. IMPORTANCEThe antiviral response is largely regulated by post-translation modifications (PTM), including ADP-ribosylation. PARP14 is an ADP-ribosyltransferase that is upregulated by interferon and is under positive selection, indicating that it is involved in host-pathogen conflict. However, no anti-viral function has been described for PARP14. Here, we found that PARP14 represses both coronavirus and HSV-1 replication, demonstrating that PARP14 has antiviral functions. Surprisingly, we also found that PARP14 also has pro-viral functions, as it was critical for the efficient replication of VSV. These data indicate that PARP14 has both proviral and antiviral functions. Defining the mechanisms used by PARP14 to both repress and promote virus replication will provide new insights into how PARPs regulate virus infection.

microbiology↗

bioRxiv2023

Autoimmunity associated allele of tyrosine phosphatase gene PTPN22 enhances anti-viral immunity

AbstractThe 1858C>T allele of the tyrosine phosphatase PTPN22 is present in 5-10% of the North American population and is strongly associated with numerous autoimmune diseases. Although research has been done to define how this allele potentiates autoimmunity, the influence PTPN22 and its pro-autoimmune allele has in anti-viral immunity remains poorly defined. Here, we use single cell RNA- sequencing and functional studies to interrogate the impact of this pro- autoimmune allele on anti-viral immunity during Lymphocytic Choriomeningitis Virus clone 13 (LCMV-cl13) infection. Mice homozygous for this allele (PEP- 619WW) clear the LCMV-cl13 virus whereas wildtype (PEP-WT) mice cannot. This is associated with enhanced anti-viral CD4 T cell responses and a more immunostimulatory CD8- cDC phenotype. Adoptive transfer studies demonstrated that PEP-619WW enhanced anti-viral CD4 T cell function through virus-specific CD4 T cell intrinsic and extrinsic mechanisms. Taken together, our data show that the pro-autoimmune allele of Ptpn22 drives a beneficial anti-viral immune response thereby preventing what is normally a chronic virus infection. Author SummaryPTPN22 and its alternative allele, 1858C>T, has largely been studied in the context of autoimmunity. Through these studies, researchers defined roles for PTPN22 in regulating T lymphocyte activation, myeloid cell cytokine production, and macrophage polarization. Despite these immune pathways being critical for anti-viral immunity, little work has studied how this allele impacts virus infection. In this study, we examine gene expression and function of immune cell subsets to demonstrate how a common allelic variant of PTPN22, which strongly increases the risk of autoimmune disease, promotes successful clearance of an otherwise chronic viral infection.

immunology↗

bioRxiv2023

PARP12 is required to repress the replication of a Mac1 mutant coronavirus in a cell and tissue specific manner

ADP-ribosyltransferases (ARTs) mediate the transfer of ADP-ribose from NAD+ to protein or nucleic acid substrates. This modification can be removed by several different types of proteins, including macrodomains. Several ARTs, also known as PARPs, are stimulated by interferon, indicating ADP-ribosylation is an important aspect of the innate immune response. All coronaviruses (CoVs) encode for a highly conserved macrodomain (Mac1) that is critical for CoVs to replicate and cause disease, indicating that ADP-ribosylation can effectively control coronavirus infection. Our siRNA screen indicated that PARP12 might inhibit the replication of a MHV Mac1 mutant virus in bone-marrow derived macrophages (BMDMs). To conclusively demonstrate that PARP12 is a key mediator of the antiviral response to CoVs both in cell culture and in vivo, we produced PARP12-/- mice and tested the ability of MHV A59 (hepatotropic/neurotropic) and JHM (neurotropic) Mac1 mutant viruses to replicate and cause disease in these mice. Notably, in the absence of PARP12, Mac1 mutant replication was increased in BMDMs and in mice. In addition, liver pathology was also increased in A59 infected mice. However, the PARP12 knockout did not restore Mac1 mutant virus replication to WT virus levels in all cell or tissue types and did not significantly increase the lethality of Mac1 mutant viruses. These results demonstrate that while PARP12 inhibits MHV Mac1 mutant virus infection, additional PARPs or innate immune factors must contribute to the extreme attenuation of this virus in mice. IMPORTANCEOver the last decade, the importance of ADP-ribosyltransferases (ARTs), also known as PARPs, in the antiviral response has gained increased significance as several were shown to either restrict virus replication or impact innate immune responses. However, there are few studies showing ART-mediated inhibition of virus replication or pathogenesis in animal models. We found that the CoV macrodomain (Mac1) was required to prevent ART-mediated inhibition of virus replication in cell culture. Here, using knockout mice, we found that PARP12, an interferon-stimulated ART, was required to repress the replication of a Mac1 mutant CoV both in cell culture and in mice, demonstrating that PARP12 represses coronavirus replication. However, the deletion of PARP12 did not fully rescue Mac1 mutant virus replication or pathogenesis, indicating that multiple PARPs function to counter coronavirus infection.

microbiology↗

bioRxiv2021

Pro-autoimmune allele of tyrosine phosphatase, PTPN22, enhances tumor immunity

The 1858C>T allele of the tyrosine phosphatase PTPN22 (causing amino acid substitution R620W in encoded protein Lyp) is present in 5-10% of the North American population and is strongly associated with numerous autoimmune diseases. Although much research has been done to define how this allele potentiates autoimmunity, the influence PTPN22 and its pro-autoimmune allele has in tumor immunity is poorly defined. To interrogate the role this allele may have in the anti-tumor immune response, we used CRISPR/Cas9 to generate mice in which the ortholog of Lyp, PEP, is mutated at position 619 to produce the relevant pro-autoimmune mutation (R619W). Results of this study show that mice homozygous for this alteration (PEP-619WW) resist tumor growth as compared with wildtype mice. Consistent with these results, tumors from PEP-619WW mice have more CD45 infiltrates containing more activated CD8 T cell and CD4 T cells. Additionally, there are more cDC1 cells and less MDSCs in tumors from PEP-619WW mice. Interestingly, the tumor infiltrating PEP-619WW cDC1s have decreased PD-L1 expression compared to cDC1s from PEP-WT mice. Taken together, our data show that the pro-autoimmune allele of Ptpn22 drives a strong anti-tumor response in innate and adaptive immune cells resulting in superior control of tumors.

immunology↗

bioRxiv2019

Conditional silencing of H-2Db class I molecule expression on dendritic cells modulates the protective and pathogenic kinetics of virus-antigen specific CD8 T cell responses during Theiler’s Virus infection

Theilers murine encephalomyelitis virus (TMEV) infection of the central nervous system is rapidly cleared in C57BL/6 mice by an anti-viral CD8 T cell response restricted by the MHC class I molecule, H-2Db. While the CD8 T cell response against neurotropic viruses is well characterized, the identity and function of the antigen presenting cell(s) involved in this process is(are) less well defined. To address this gap in knowledge, we developed a novel C57BL/6 H-2Db conditional knockout mouse that expresses an H-2Db transgene in which the transmembrane domain locus is flanked by LoxP sites. We crossed these H-2Db LoxP mice with MHC class I-deficient mice expressing Cre-recombinase under either the CD11c or LysM promoter in order to silence H-2Db restricted antigen presentation predominantly in dendritic cells or macrophages, respectively. Upon challenge with intracranial TMEV infection, we observe that CD11c+ APCs are critical for early priming of CD8 T cells against the immunodominant TMEV peptide VP2121-130 presented in the context of the H-2Db molecule. This stands in stark contrast to later time points post TMEV infection where CD11c+ APCs appear dispensable for the activation of antigen-specific T cells; the functionality of these late-arising antiviral CD8 T cells is reflected in the restoration of viral control at later time points. These late-arising CD8 T cells also retain their capacity to induce blood-brain barrier disruption. In contrast, when H-2Db restricted antigen presentation was selectively silenced in LysM+ APCs there was no overt impact on the priming of Db:VP2121-130 epitope-specific CD8 T cells, although a modest reduction in immune cell entry into the CNS was observed. This work establishes a model system which enables critical dissection of MHC class I restricted antigen presentation to T cells, revealing cell specific and temporal features involved in the generation of antiviral CD8 T cell responses. Employing this novel system, we established CD11c+ cells as a pivotal driver of acute, but not later-arising, antiviral CD8 T cell responses against the TMEV immunodominant epitope VP2121-130, with functional implications both for T cell-mediated viral control and immunopathology.

immunology↗