Choi, BR;Johnson, KR;Maric, D;McGavern, DB;
PMID: 37248420 | DOI: 10.1038/s41590-023-01521-1
Cerebrovascular injury (CVI) is a common pathology caused by infections, injury, stroke, neurodegeneration and autoimmune disease. Rapid resolution of a CVI requires a coordinated innate immune response. In the present study, we sought mechanistic insights into how central nervous system-infiltrating monocytes program resident microglia to mediate angiogenesis and cerebrovascular repair after an intracerebral hemorrhage. In the penumbrae of human stroke brain lesions, we identified a subpopulation of microglia that express vascular endothelial growth factor A. These cells, termed 'repair-associated microglia' (RAMs), were also observed in a rodent model of CVI and coexpressed interleukin (IL)-6Ra. Cerebrovascular repair did not occur in IL-6 knockouts or in mice lacking microglial IL-6Ra expression and single-cell transcriptomic analyses revealed faulty RAM programming in the absence of IL-6 signaling. Infiltrating CCR2+ monocytes were the primary source of IL-6 after a CVI and were required to endow microglia with proliferative and proangiogenic properties. Faulty RAM programming in the absence of IL-6 or inflammatory monocytes resulted in poor cerebrovascular repair, neuronal destruction and sustained neurological deficits that were all restored via exogenous IL-6 administration. These data provide a molecular and cellular basis for how monocytes instruct microglia to repair damaged brain vasculature and promote functional recovery after injury.
Cancer immunology research
Reschke, R;Shapiro, JW;Yu, J;Rouhani, SJ;Olson, DJ;Zha, Y;Gajewski, TF;
PMID: 35977003 | DOI: 10.1158/2326-6066.CIR-22-0362
Immune checkpoint blockade is therapeutically successful for many patients across multiple cancer types. However, immune-related adverse events (irAE) frequently occur and can sometimes be life threatening. It is critical to understand the immunologic mechanisms of irAEs with the goal of finding novel treatment targets. Herein, we report our analysis of tissues from patients with irAE dermatitis using multiparameter immunofluorescence (IF), spatial transcriptomics, and RNA in situ hybridization (RISH). Skin psoriasis cases were studied as a comparison, as a known Th17-driven disease, and colitis was investigated as a comparison. IF analysis revealed that CD4+ and CD8+ tissue-resident memory T (TRM) cells were preferentially expanded in the inflamed portion of skin in cutaneous irAEs compared with healthy skin controls. Spatial transcriptomics allowed us to focus on areas containing TRM cells to discern functional phenotype and revealed expression of Th1-associated genes in irAEs, compared with Th17-asociated genes in psoriasis. Expression of PD-1, CTLA-4, LAG-3, and other inhibitory receptors was observed in irAE cases. RISH technology combined with IF confirmed expression of IFNγ, CXCL9, CXCL10, and TNFα in irAE dermatitis, as well as IFNγ within TRM cells specifically. The Th1-skewed phenotype was confirmed in irAE colitis cases compared with healthy colon.
Urrutia AA, Afzal A, Nelson J, Davidoff O, Gross KW, Haase VH.
PMID: 27683416 | DOI: 10.1182/blood-2016-05-713545
A classic response to systemic hypoxia is the increased production of red blood cells due to hypoxia-inducible factor (HIF)-mediated induction of erythropoietin (EPO). EPO is a glycoprotein hormone that is essential for normal erythropoiesis and is predominantly synthesized by peritubular renal interstitial fibroblast-like cells, which express cellular markers characteristic of neuronal cells and pericytes. To investigate whether the ability to synthesize EPO is a general functional feature of pericytes, we used conditional gene targeting to examine the von Hippel-Lindau/prolyl-4-hydroxylase domain (PHD)/HIF axis in cell-expressing neural glial antigen 2, a known molecular marker of pericytes in multiple organs. We found that pericytes in the brain synthesized EPO in mice with genetic HIF activation and were capable of responding to systemic hypoxia with the induction of Epo. Using high-resolution multiplex in situ hybridization, we determined that brain pericytes represent an important cellular source of Epo in the hypoxic brain (up to 70% of all Epo-expressing cells). We furthermore determined that Epo transcription in brain pericytes was HIF-2 dependent and cocontrolled by PHD2 and PHD3, oxygen- and 2-oxoglutarate-dependent prolyl-4-hydroxylases that regulate HIF activity. In summary, our studies provide experimental evidence that pericytes in the brain have the ability to function as oxygen sensors and respond to hypoxia with EPO synthesis. Our findings furthermore suggest that the ability to synthesize EPO may represent a functional feature of pericytes in the brain and kidney.
Du L, Hu X, Yang W, Yasheng H, Liu S, Zhang W, Zhou Y, Cui W, Zhu J, Qiao Z, Maoying Q, Chu Y, Zhou H, Wang Y, Mi W.
PMID: 31087583 | DOI: 10.1002/glia.23639
Interleukin-33 (IL-33) and its receptor ST2 contribute to spinal glial activation and chronic pain. A recent study showed that peripheral IL-33 plays a pivotal role in the pathogenesis of chronic itch induced by poison ivy. However, how IL-33/ST2 signaling in the spinal cord potentially mediates chronic itch remains elusive. Here, we determined that St2-/- substantially reduced scratching behaviors in 2,4-dinitrofluorobenzene (DNFB)-induced allergic contact dermatitis (ACD) as well as acetone and diethylether followed by water-induced dry skin in mice. Intrathecal administration of the neutralizing anti-ST2 or anti-IL-33 antibody remarkably decreased the scratching response in DNFB-induced ACD mice. Expression of spinal IL-33 and ST2 significantly increased in ACD mice, as evidenced by increased mRNA and protein levels. Immunofluorescence and in situ hybridization demonstrated that increased expression of spinal IL-33 was predominant in oligodendrocytes and astrocytes, whereas ST2 was mainly expressed in astrocytes. Further studies showed that in ACD mice, the activation of astrocytes and increased phosphorylation of signal transducer and activator of transcription 3 (STAT3) were markedly attenuated by St2-/- . Intrathecal injection of Janus Kinase 2 Inhibitor AG490 significantly alleviated scratching behaviors in ACD mice. rIL-33 pretreatment exacerbated gastrin-releasing peptide (GRP)-evoked scratching behaviors. This increased gastrin-releasing peptide receptor (GRPR) expression was abolished by St2-/- . Tnf-α upregulation was suppressed by St2-/- . Our results indicate that the spinal IL-33/ST2 signaling pathway contributes to chronic itch via astrocytic JAK2-STAT3 cascade activation, promoting TNF-α release to regulate the GRP/GRPR signaling-related itch response. Thus, these findings provide a potential therapeutic option for treating chronic pruritus.
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
Velazquez-Sanchez, C;Muresan, L;Marti-Prats, L;Belin, D;
PMID: 36635597 | DOI: 10.1038/s41386-022-01522-y
Some compulsive disorders have been considered to stem from the loss of control over coping strategies, such as displacement. However, the cellular mechanisms involved in the acquisition of coping behaviours and their subsequent compulsive manifestation in vulnerable individuals have not been elucidated. Considering the role of the locus coeruleus (LC) noradrenaline-dependent system in stress and related excessive behaviours, we hypothesised that neuroplastic changes in the LC may be associated with the acquisition of an adjunctive polydipsic water drinking, a prototypical displacement behaviour, and the ensuing development of compulsion in vulnerable individuals. Thus, male Sprague Dawley rats were characterised for their tendency, or not, to develop compulsive polydipsic drinking in a schedule-induced polydipsia (SIP) procedure before their fresh brains were harvested. A new quantification tool for RNAscope assays revealed that the development of compulsive adjunctive behaviour was associated with a low mRNA copy number of the plasticity marker Arc in the LC which appeared to be driven by specific adaptations in an ensemble of tyrosine hydroxylase (TH)+, zif268- neurons. This ensemble was specifically engaged by the expression of compulsive adjunctive behaviour, not by stress, because its functional recruitment was not observed in individuals that no longer had access to the water bottle before sacrifice, while it consistently correlated with the levels of polydipsic water drinking only when it had become compulsive. Together these findings suggest that downregulation of Arc mRNA levels in a population of a TH+/zif268- LC neurons represents a signature of the tendency to develop compulsive coping behaviours.
Ribeiro, M;Ayupe, AC;Beckedorff, FC;Levay, K;Rodriguez, S;Tsoulfas, P;Lee, JK;Nascimento-Dos-Santos, G;Park, KK;
PMID: 35738417 | DOI: 10.1016/j.expneurol.2022.114147
Following injury in the central nervous system, a population of astrocytes occupy the lesion site, form glial bridges and facilitate axon regeneration. These astrocytes originate primarily from resident astrocytes or NG2+ oligodendrocyte progenitor cells. However, the extent to which these cell types give rise to the lesion-filling astrocytes, and whether the astrocytes derived from different cell types contribute similarly to optic nerve regeneration remain unclear. Here we examine the distribution of astrocytes and NG2+ cells in an optic nerve crush model. We show that optic nerve astrocytes partially fill the injury site over time after a crush injury. Viral mediated expression of a growth-promoting factor, ciliary neurotrophic factor (CNTF), in retinal ganglion cells (RGCs) promotes axon regeneration without altering the lesion size or the degree of lesion-filling GFAP+ cells. Strikingly, using inducible NG2CreER driver mice, we found that CNTF overexpression in RGCs increases the occupancy of NG2+ cell-derived astrocytes in the optic nerve lesion. An EdU pulse-chase experiment shows that the increase in NG2 cell-derived astrocytes is not due to an increase in cell proliferation. Lastly, we performed RNA-sequencing on the injured optic nerve and reveal that CNTF overexpression in RGCs results in significant changes in the expression of distinct genes, including those that encode chemokines, growth factor receptors, and immune cell modulators. Even though CNTF-induced axon regeneration has long been recognized, this is the first evidence of this procedure affecting glial cell fate at the optic nerve crush site. We discuss possible implication of these results for axon regeneration.
Mucosal IFNγ production and potential role in protection in Escherichia coli O157:H7 vaccinated and challenged cattle
Schaut, RG;Palmer, MV;Boggiatto, PM;Kudva, IT;Loving, CL;Sharma, VK;
PMID: 33963240 | DOI: 10.1038/s41598-021-89113-7
Shiga-toxin producing Escherichia coli O157:H7 (O157)-based vaccines can provide a potential intervention strategy to limit foodborne zoonotic transmission of O157. While the peripheral antibody response to O157 vaccination has been characterized, O157-specific cellular immunity at the rectoanal junction (RAJ), a preferred site for O157 colonization, remains poorly described. Vaccine induced mucosal O157-specific antibodies likely provide some protection, cellular immune responses at the RAJ may also play a role in protection. Distinct lymphoid follicles were increased in the RAJ of vaccinated/challenged animals. Additionally, increased numbers of interferon (IFN)γ-producing cells and γδ + T cells were detected in the follicular region of the RAJ of vaccinated/challenged animals. Likewise, adjuvanted-vaccine formulation is critical in immunogenicity of the O157 parenteral vaccine. Local T cell produced IFNγ may impact epithelial cells, subsequently limiting O157 adherence, which was demonstrated using in vitro attachment assays with bovine epithelial cells. Thus, distinct immune changes induced at the mucosa of vaccinated and challenged animals provide insight of mechanisms associated with limiting O157 fecal shedding. Enhancing mucosal immunity may be critical in the further development of efficacious vaccines for controlling O157 in ruminants and thus limiting O157 transmission to humans.
Zhu H, Meissner LE, Byrnes C, Tuymetova G, Tifft CJ, Proia RL
PMID: 32179479 | DOI: 10.1016/j.isci.2020.100957
The SUSD4 (Sushi domain-containing protein 4) gene encodes a complement inhibitor that is frequently deleted in 1q41q42 microdeletion syndrome, a multisystem congenital disorder that includes neurodevelopmental abnormalities. To understand SUSD4's role in the mammalian nervous system, we analyzed Susd4 knockout (KO) mice. Susd4 KO mice exhibited significant defects in motor performance and significantly higher levels of anxiety-like behaviors. Susd4 KO brain had abnormal "hairy" basket cells surrounding Purkinje neurons within the cerebellum and significantly reduced dendritic spine density in hippocampal pyramidal neurons. Neurons and oligodendrocyte lineage cells of wild-type mice were found to express Susd4 mRNA. Protein expression of the complement component C1q was increased in the brains of Susd4 KO mice. Our data indicate that SUSD4 plays an important role in neuronal functions, possibly via the complement pathway, and that SUSD4 deletion may contribute to the nervous system abnormalities in patients with 1q41q42 deletions
Aloi, MS;Thompson, SJ;Quartapella, N;Noebels, JL;
PMID: 36417872 | DOI: 10.1016/j.celrep.2022.111696
Mutations in Kv1.1 (Kcna1) voltage-gated potassium channels in humans and mice generate network hyperexcitability, enhancing aberrant postnatal neurogenesis in the dentate subgranular zone, resulting in epilepsy and hippocampal hypertrophy. While Kcna1 loss stimulates proliferation of progenitor cell subpopulations, the identity of extrinsic molecular triggers linking network hyperexcitability to aberrant postnatal neurogenesis remains incomplete. System x-c (Sxc) is an inducible glutamate/cysteine antiporter that regulates extracellular glutamate. Here, we find that the functional unit of Sxc, xCT (Slc7a11), is upregulated in regions of Kcna1 knockout (KO) hippocampus, suggesting a contribution to both hyperplasia and epilepsy. However, Slc7a11 KO suppressed and rescued hippocampal enlargement without altering seizure severity in Kcna1-Slc7a11-KO mice. Microglial activation, but not astrocytosis, was also reduced. Our study identifies Sxc-mediated glutamate homeostasis as an essential non-synaptic trigger coupling aberrant postnatal neurogenesis and neuroimmune crosstalk, revealing that neurogenesis and epileptogenesis in the dentate gyrus are not mutually contingent events.
Smith HL, Freeman OJ, Butcher AJ, Holmqvist S, Humoud I, Sch�tzl T, Hughes DT, Verity NC, Swinden DP, Hayes J, de Weerd L, Rowitch DH, Franklin RJM, Mallucci GR
PMID: 31924446 | DOI: 10.1016/j.neuron.2019.12.014
Recent interest in astrocyte activation states has raised the fundamental question of how these cells, normally essential for synapse and neuronal maintenance, become pathogenic. Here, we show that activation of the unfolded protein response (UPR), specifically phosphorylated protein kinase R-like endoplasmic reticulum (ER) kinase (PERK-P) signaling-a pathway that is widely dysregulated in neurodegenerative diseases-generates a distinct reactivity state in astrocytes that alters the astrocytic secretome, leading to loss of synaptogenic function in vitro. Further, we establish that the same PERK-P-dependent astrocyte reactivity state is harmful to neurons in vivo in mice with prion neurodegeneration. Critically, targeting this signaling exclusively in astrocytes during prion disease is alone sufficient to prevent neuronal loss and significantly prolongs survival. Thus, the astrocyte reactivity state resulting from UPR over-activation is a distinct pathogenic mechanism that can by itself be effectively targeted for neuroprotection
Human Type II Taste Cells Express ACE2 and are Infected by SARS-CoV-2
The American journal of pathology
Doyle, ME;Appleton, A;Liu, QR;Yao, Q;Mazucanti, CH;Egan, JM;
PMID: 34102107 | DOI: 10.1016/j.ajpath.2021.05.010
Chemosensory changes are well-reported symptoms of SARS-CoV-2 infection. The virus targets cells for entry by binding of its spike protein to cell-surface angiotensin-converting enzyme- 2 (ACE2). It was not known whether ACE2 is expressed on taste receptor cells (TRCs) nor if TRCs are infected directly. Using an in-situ hybridization (ISH) probe and an antibody specific to ACE2, ACE2 is present on a subpopulation of TRCs, namely, Type II cells in taste buds in taste papillae. Fungiform papillae (FP) of a SARS-CoV-2+ patient exhibiting symptoms of COVID-19, including taste changes, were biopsied. Based on ISH, replicating SARS-CoV-2 was present in Type II cells. Therefore, taste Type II cells provide a potential portal for viral entry that predicts vulnerabilities to SARS-CoV-2 in the oral cavity. The continuity and cell turnover of the patient's FP taste stem cell layer were disrupted during infection and had not completely recovered 6 weeks post symptom onset. Another patient suffering post-COVID-19 taste disturbances also had disrupted stem cells. These results demonstrate the possibility that novel and sudden taste changes frequently reported in COVID-19 may be the result of direct infection of taste papillae by SARS-CoV-2. This may result in impaired taste receptor stem cell activity and suggest more work is needed to understand the acute and post-acute dynamics of viral kinetics in the human taste bud.
Influence of the microenvironment on modulation of the host response by typhoid toxin
Martin, OCB;Bergonzini, A;Lopez Chiloeches, M;Paparouna, E;Butter, D;Theodorou, SDP;Haykal, MM;Boutet-Robinet, E;Tebaldi, T;Wakeham, A;Rhen, M;Gorgoulis, VG;Mak, T;Pateras, IS;Frisan, T;
PMID: 33826883 | DOI: 10.1016/j.celrep.2021.108931
Bacterial genotoxins cause DNA damage in eukaryotic cells, resulting in activation of the DNA damage response (DDR) in vitro. These toxins are produced by Gram-negative bacteria, enriched in the microbiota of inflammatory bowel disease (IBD) and colorectal cancer (CRC) patients. However, their role in infection remains poorly characterized. We address the role of typhoid toxin in modulation of the host-microbial interaction in health and disease. Infection with a genotoxigenic Salmonella protects mice from intestinal inflammation. We show that the presence of an active genotoxin promotes DNA fragmentation and senescence in vivo, which is uncoupled from an inflammatory response and unexpectedly associated with induction of an anti-inflammatory environment. The anti-inflammatory response is lost when infection occurs in mice with acute colitis. These data highlight a complex context-dependent crosstalk between bacterial-genotoxin-induced DDR and the host immune response, underlining an unexpected role for bacterial genotoxins.
