Biology subjects

Crispo, M.

Publications and source records attributed to Crispo, M..

10 recordsLinked to original sources

bioRxiv2026

IFNγ at the crossroads of systemic protection and brain vulnerability to coronavirus infection

The COVID-19 pandemic, together with previous outbreaks caused by highly pathogenic coronaviruses, highlighted the importance of understanding the host determinants that influence pathogenesis, both to improve our understanding of disease mechanisms, and to strengthen preparedness for future outbreaks. In our previous work we demonstrated dysregulation of IFN{gamma} response genes in COVID-19 patients, associated with both age and viral burden, positioning IFN{gamma} as a key mediator of host defense against SARS-CoV-2. Here, we used a preclinical murine model of coronavirus infection based on murine hepatitis virus (MHV-A59), widely validated for studying SARS-CoV-2 pathogenesis, together with IFN{gamma} knockout (IFN{gamma}-KO) mice to investigate the role of this cytokine during infection. We performed a comprehensive morphological, biochemical, hematological and proteomic characterization of infected wild-type (WT) and IFN{gamma}-deficient mice. Plasma proteomics revealed impaired inflammatory and coagulation-related responses in IFN{gamma}-KO animals compared to WT controls. We found increased viral load and infectious particles in peripheral organs, including liver, spleen, heart and muscle in IFN{gamma}-KO mice, whereas these were significantly reduced in the brain. Region-specific analysis further demonstrated decreased viral load in the prefrontal cortex and hippocampus of IFN{gamma}-KO animals. Consistently, bioinformatics analysis of transcriptomics data of IFN{gamma}-treated primary neuron cultures, together with frontal cortex from human COVID-19 patients, revealed activation of neuroinflammatory and neurological disease-associated pathways, supporting a role for IFN{gamma} in driving brain inflammatory responses during coronavirus infection. Together, these findings reveal a dual role for IFN{gamma} during coronavirus infection: it is important for controlling systemic viral dissemination and limiting peripheral tissue damage, yet it may also promote viral susceptibility and exacerbated inflammatory responses in the brain. These results support IFN{gamma} modulation as a potential therapeutic strategy to prevent or mitigate neurological complications associated with COVID-19. Author SummaryViral infections are controlled by the immune system, but the same responses that protect the body can sometimes contribute to tissue damage and disease. We investigated how a key immune molecule, called Interferon Gamma, influences the outcome of Coronavirus infection in different parts of the body. Using a mouse model of Coronavirus infection with Interferon Gamma deficiency, we found that this molecule plays two opposing roles: it helps control the spread of the virus throughout the body, but it also increases vulnerability of the brain to infection and inflammation. When this immune signal was absent, animals showed higher amounts of virus in several peripheral organs but surprisingly had lower levels of virus in specific brain regions. We further found that this immune response was associated with changes in inflammation and neurological processes in human data. Our findings reveal that antiviral immunity is not always uniformly protective and that its effects depend on the tissue involved. Understanding this balance may help guide future approaches to reduce virus-associated complications while preserving the protective functions of the immune response.

microbiology↗

bioRxiv2026

Extended tissue tropism and vertical transmission in a murine model of Mayaro virus infection

Mayaro virus (MAYV) is an emerging mosquito-borne alphavirus associated with acute febrile illness and persistent arthralgia, with increasing reports in Latin America and potential for geographic expansion. However, its dissemination dynamics, tissue tropism and transmission routes remain incompletely defined. Here, we developed a murine model to characterize systemic viral dissemination, tissue tropism and the impact of gestational stage on maternal-fetal outcomes. A nanoluciferase-expressing MAYV reporter enabled non-invasive in vivo imaging, revealing rapid and widespread systemic dissemination under controlled conditions. Complementary infection with wild-type (WT) virus confirmed broad tropism across lymphoid, musculoskeletal and reproductive tissues. At 24 hours post-infection (hpi), viral distribution was relatively homogeneous across tissues, whereas at 48 hpi, tissue-specific differences emerged, with increased viral loads in selected organs, including the spleen and male reproductive tissues. Transient sex-dependent differences were observed at 24 hpi but were not sustained at later time points. Hematological and biochemical analyses revealed early systemic alterations consistent with changes in leukocyte distribution during acute infection. Infectious viral particles were detected in reproductive tissues of both sexes, including in sperm, supporting the biological plausibility of non-vector transmission, although detection in exposed animals was limited. Gestational stage influenced infection outcomes: early gestation (infected at 7.5-8.5 dpc; analyzed at 9.5-10.5 dpc) was associated with detection of infectious virus in fetal tissues, whereas mid-gestation (infected at 13.5-14.5 dpc; analyzed at 15.5-16.5 dpc) showed no detectable infectious virus in fetuses despite evidence of viral antigen persistence and sustained infectious viral presence in maternal and placental compartments. Together, these findings provide a preclinical framework for investigating MAYV pathogenesis and underscore the role of tissue tropism and gestational context in shaping infection dynamics and maternal-fetal involvement. Author summaryMayaro virus (MAYV) is an emerging mosquito-borne virus that causes fever and long-lasting joint pain, with increasing reports in Latin America and potential for wider geographic spread. Despite its growing relevance, key aspects of MAYV pathogenesis remain to be fully defined, including the mechanisms underlying systemic dissemination and tissue tropism, as well as its potential to affect pregnancy or be transmitted through non-vector routes. Here, we used a mouse model with a luminescent reporter virus to track MAYV dissemination in vivo, revealing rapid and widespread distribution across multiple tissues. In studies using wild-type virus, infectious virus was detected not only in muscle and immune-related organs but also in reproductive tissues of both females and males. Importantly, gestational stage influenced viral distribution. When infection occurred early in gestation, infectious viral particles were detected in fetal tissues. In contrast, at later stages of pregnancy, infectious virus was no longer detectable in fetuses, despite evidence of viral antigen persistence and sustained infectious viral presence in maternal and placental tissues. Together, these findings advance our understanding of MAYV infection, highlight gestational timing as a factor associated with fetal exposure and suggest the possibility of transmission through routes other than mosquitoes, providing a framework for future studies on this emerging virus.

microbiology↗

bioRxiv2025

Detection and isolation of H5N1 clade 2.3.4.4b high pathogenicity avian influenza virus from ticks (Ornithodoros maritimus) recovered from a naturally infected slender-billed gull (Chroicocephalus genei)

Laridae birds, such as gulls, are known reservoirs of H13 and H16 low pathogenicity avian influenza virus (LPAIV) subtypes. However, during the recent outbreaks linked to the reemergence of high pathogenicity avian influenza virus (HPAIV) H5N1 clade 2.3.4.4b of the Goose/Guangdong lineage, European populations of Laridae birds suffered significant losses. HPAI cases were reported not only along the coastlines but also inland areas, particularly in France and Central Europe. During a diagnostic investigation of a group of Laridae birds, part of a HPAIV outbreak reported in the South of France in 2023, larval stages of Ornithodoros maritimus, a nidicolous soft tick parasitizing seabirds, were recovered from a slender-billed gull (Chroicocephalus genei). Affected birds exhibited gross and histopathological lesions consistent with systemic HPAIV infection. Immunohistochemistry revealed marked neurotropism, oculotropism and multicentric epitheliotropism. Viral isolation and sequencing analysis confirmed the presence of HPAIV H5N1 clade 2.3.4.4b in both the gull and ectoparasites, showing from 99.64% to 100% nucleotide identity across five of eight RNA segments. While additional research is needed to properly assess the vector competence of O. maritimus for HPAIV, ticks may represent an interesting non-invasive surveillance tool for these viruses. This is the first time a HPAIV has been successfully isolated from tick larvae. These findings represent a first step toward understanding the potential role played by ticks in the spread of avian influenza viruses within marine bird colonies and among other ecosystems, considering the occurrence of specific behavioral traits, such as kleptoparasitim and the position of gulls at the interface between wild and domestic species.

microbiology↗

bioRxiv2024

Adipocyte-specific deletion of Dbc1 does not recapitulate healthy obesity phenotype but suggests regulation of inflammation signaling

The protein Deleted in Breast Cancer 1 (DBC1), a regulator of several transcription factors and epigenetic modulators, plays determinant roles in metabolism regulation, obesity and aging-related processes. Knockout mice for Dbc1, develop morbid obesity but are protected against liver steatosis, insulin resistance and atherosclerosis. We have proposed that this healthy obesity phenotype was mainly due to the expansion of adipose tissue, avoiding free-fatty acid spillover and metabolic damage in peripheral tissues. To gain more insight about the role of Dbc1 in adipose cells during obesity and its impact on metabolic dysregulation, we generated a conditional Dbc1 KO mouse and backcrossed it with CRE-AdipoQ transgenic mice, aiming to abrogate Dbc1 expression in all mature adipocytes (cAT-Dbc1). cAT-Dbc1 mice showed deletion of Dbc1 specifically in mature adipocytes in different fat depots. We tested the effect of Dbc1 deletion in adipocytes on different aspects of metabolic regulation in male and female mice fed in normal chow and high-fat diets. We found that deletion of Dbc1 in mature adipocytes had no effect on weight gain, glucose tolerance and other markers of metabolic dysregulation, regardless sex. However, Dbc1 KO adipocytes displayed an mRNA expression profile consistent with increased inflammation during obesity. Our results suggest that the healthy phenotype displayed in the whole body Dbc1 KO obese mice is not due to the protein function in mature adipocytes and might involve other cell types present in adipose tissue. Instead, the specific deletion of Dbc1 in mature adipocytes highlights a novel role of Dbc1 in inflammation signaling during obesity.

physiology↗

bioRxiv2023

High pathogenicity avian influenza A (H5N1) clade 2.3.4.4b virus infection in a captive Tibetan black bear (Ursus thibetanus): investigations based on paraffin-embedded tissues, France, 2022

High pathogenicity avian influenza viruses H5Nx (HPAIVs) of clade 2.3.4.4b have been circulating increasingly in both wild and domestic birds in recent years. In turn, this has led to an increase in the number of spillovers events affecting mammals. In November 2022, a HPAIV H5N1 caused an outbreak in a zoological park in the south of France, resulting in the death of a Tibetan black bear (Ursus thibetanus) and several captive and wild bird species. We detected the virus in various tissues of the bear and a wild black-headed gull found dead in its enclosure using histopathology, two different in-situ detection techniques and next generation sequencing, all performed on formalin fixed paraffin embedded tissues. Phylogenetic analysis performed on HA gene segment showed that bear and gull strains shared 99.998% genetic identity, making the bird strain the closest related one. We detected the PB2 E627K mutation in minute quantities in the gull, whereas it predominated in the bear, which suggests that this mammalian adaptation marker was selected during the bear infection. Our results provide the first molecular and histopathological characterization of an H5N1 virus infection in this bear species.

microbiology↗

bioRxiv2023

The Feather Epithelium Contributes to the Dissemination and Ecology of clade 2.3.4.4b H5 High Pathogenicity Avian Influenza Virus in Ducks

Immature feathers are known replication sites for high pathogenicity avian influenza viruses (HPAIVs) in poultry. However, it is unclear whether feathers play an active role in viral transmission. This study aims to investigate the contribution of the feather epithelium to the dissemination of clade 2.3.4.4b goose/Guangdong/1996 lineage H5 HPAIVs in the environment, based on natural and experimental infections of domestic ducks. During the 2016-22 outbreaks, H5 HPAIVs exhibited persistent and marked feather epitheliotropism in naturally infected commercial ducks. Infection of feathers resulted in epithelial necrosis, disruption, and the production and release of infectious virions. Viral and feather antigens colocalized in dust samples obtained from poultry barns housing naturally infected birds. In summary, the feather epithelium contributes to viral replication, and it is a likely source of environmental infectious material. This underestimated excretion route could greatly impact the ecology of HPAIVs, facilitating airborne and preening-related infections within a flock, and promoting prolonged viral infectivity and long-distance viral transmission between poultry farms. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=112 SRC="FIGDIR/small/550633v1_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@16f6b24org.highwire.dtl.DTLVardef@1e33c82org.highwire.dtl.DTLVardef@199b745org.highwire.dtl.DTLVardef@cf2024_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2022

The lectin receptor Clec4F participates in the capture of circulating parasite mucins by Kupffer cells in cystic echinococcosis.

Cystic echinococcosis is caused by the larval stages (hydatids) of cestode parasites belonging to the species cluster Echinococcus granulosus sensu lato, with E. granulosus sensu stricto being the main infecting species. Hydatids are bladder-like structures that attain large sizes within various internal organs of livestock ungulates and humans. Hydatids are protected by the massive acellular laminated layer (LL), composed mainly by mucins. Parasite growth requires LL turnover, and abundant LL-derived particles are found at infection sites in infected humans, raising the question of how LL materials are dealt with by the hosts. In this article, we show that E. granulosus sensu stricto LL mucins injected into mice are taken up by Kupffer cells, the liver macrophages exposed to the vascular space. This uptake is largely dependent on the intact mucin glycans and on Clec4F, a C-type lectin receptor which in rodents is selectively expressed in Kupffer cells. This uptake mechanism operates on mucins injected both in soluble form i.v. and in particulate form i.p. In mice harbouring intraperitoneal infections by the same species, LL mucins were found essentially only at the infection site and in the liver, where they were taken up by Kupffer cells via Clec4F. Therefore, shed LL materials circulate in the host and Kupffer cells can act as a sink for these materials even when the parasite grows in sites other than the liver.

immunology↗

bioRxiv2022

Trypanosoma cruzi isolates naturally adapted to congenital transmission display a unique strategy of transplacental passage

Chagas disease is mainly transmitted by vertical transmission (VT) in non-endemic areas and in endemic areas where vector control programs have been successful. For the present study, we isolated natural strains vertically transmitted through three generations and proceeded to study their molecular mechanism of VT. No parasitemia was detected in immunocompetent mice, but they were able to induce an immune response and colonize different organs. VT experiments revealed that infection with the different strains did not affect mating, pregnancy or resorptions, but despiting low parasitemia, VT strains reached the placenta and resulted in higher vertical transmission rates than strains of either moderate or high virulence. While the virulent strain modulated more than 2500 placental genes, VT strains modulated 150, and none of the modulated genes is shared between them. VT strains downregulate genes associated with cell division and replication and upregulate immunomodulatory genes leading to anti-inflammatory responses and tolerance. The virulent strain stimulates a strong pro-inflammatory immune response, and this molecular footprint correlated with histopathological analyses. We herein describe a unique placental response regarding the passage of T cruzi VT isolates across the maternal-fetal interphase, challenging the current knowledge derived mainly from studies of laboratory-adapted or highly virulent strains.

microbiology↗

bioRxiv2021

Generation and characterization of Ccdc28b mutant mice links the Bardet-Biedl associated gene with social behavioral phenotypes

CCDC28B (coiled-coil domain-containing protein 28B) was identified as a modifier in the ciliopathy Bardet-Biedl syndrome (BBS). Our previous work in cells and zebrafish showed that CCDC28B plays a role regulating cilia length in a mechanism that is not completely understood. Here we report the generation of a Ccdc28b mutant mouse using CRISPR/Cas9 (Ccdc28b mut). After confirming the depletion of Ccdc28b we performed a phenotypic characterization showing that Ccdc28b mut animals present a mild phenotype: i) do not present clear structural cilia affectation, although we did observe mild defects in cilia density and cilia length in some tissues, ii) reproduce normally, and iii) do not develop retinal degeneration or obesity, two hallmark features of reported BBS murine models. In contrast, Ccdc28b mut mice did show clear social interaction defects as well as stereotypical behaviors suggestive of autism spectrum disorder (ASD). This finding is indeed relevant regarding CCDC28B as a modifier of BBS since behavioral phenotypes have been documented in BBS. Importantly however, our data suggests a possible causal link between CCDC28B and ASD-like phenotypes that exceeds the context of BBS: filtering for rare deleterious variants, we found CCDC28B mutations in eight probands from the Simmons Simplex Collection cohort. Furthermore, a phenotypic analysis showed that CCDC28B mutation carriers present lower BMI and mild communication defects compared to a randomly selected sample of SSC probands. Thus, our results suggest that mutations in CCDC28B lead to mild autism-like features in mice and humans. Overall, this work reports a novel mouse model that will be key to continue evaluating genetic interactions in BBS, deciphering the contribution of CCDC28B to modulate the presentation of BBS phenotypes. In addition, our data underscores a novel link between CCDC28B and ASD-like phenotypes, providing a novel opportunity to further our understanding of the genetic, cellular, and molecular basis of ASD. AUTHOR SUMMARYBardet-Biedl syndrome (BBS) is caused by mutations in any of 21 genes known to date. In some families, BBS can be inherited as an oligogenic trait whereby mutations in more than one BBS gene collaborate in the presentation of the syndrome. In addition, CCDC28B was identified as a modifier of BBS, associated with a more severe presentation of the syndrome. Different mechanisms, all relying on functional redundancy, have been proposed to explain this genetic interaction and the characterization of different BBS proteins supported this possibility as they were shown to play roles in the same cellular organelle, the primary cilium. Similarly, CCDC28B also participates in cilia biology regulating the length of the organelle: knockdown of CCDC28B in cells results in cilia shortening and depletion in zebrafish also results in early embryonic phenotypes characteristic of other cilia mutants. Here, we sought to generate a mouse Ccdc28b mutant to determine whether it would be sufficient to cause a ciliopathy phenotype, and to generate a reagent critical to further dissect its modifying role in the context of BBS. Overall, Ccdc28b mutant mice presented a mild phenotype, a finding fully compatible with a modifier rather than a causal BBS gene. In addition, we found that Ccdc28b mutants showed a clear autism-like behavior, and autism is indeed a feature of several BBS patients. Importantly, we identified multiple individuals with autism from the Simmos Simplex Collection to carry disruptive mutations in CCDC28B suggesting that this gene is causally associated with autism independently of BBS.

genetics↗

bioRxiv2020

Ivermectin reduces coronavirus infection in vivo: a mouse experimental model

SARS-CoV2 is a single strand RNA virus member of the type 2 coronavirus family, responsible for causing COVID-19 disease in humans. The objective of this study was to test the ivermectin drug in a murine model of coronavirus infection using a type 2 family RNA coronavirus similar to SARS-CoV2, the mouse hepatitis virus (MHV). BALB/cJ female mice were infected with 6,000 PFU of MHV-A59 (Group Infected; n=20) and immediately treated with one single dose of 500 g/kg of ivermectin (Group Infected + IVM; n=20), or were not infected and treated with PBS (Control group; n=16). Five days after infection/treatment, mice were euthanized to obtain different tissues to check general health status and infection levels. Overall results demonstrated that viral infection induces the typical MHV disease in infected animals, with livers showing severe hepatocellular necrosis surrounded by a severe lymphoplasmacytic inflammatory infiltration associated with a high hepatic viral load (52,158 AU), while ivermectin administration showed a better health status with lower viral load (23,192 AU; p<0.05) and few livers with histopathological damage (p<0.05), not showing statistical differences with control mice (P=NS). Furthermore, serum transaminase levels (aspartate aminotransferase and alanine aminotransferase) were significantly lower in treated mice compared to infected animals. In conclusion, ivermectin seems to be effective to diminish MHV viral load and disease in mice, being a useful model for further understanding new therapies against coronavirus diseases.

pathology↗