Gabriel Henrique Campolina-Silva

Zika virus (ZIKV) is an emerging arbovirus belonging to the Flaviviridae family and Orthoflavivirus genus, with a pronounced tropism for the central nervous system (CNS), where it induces neuroinflammation and neuronal death. ZIKV is known to exploit host cellular mechanisms, including the activation of survival pathways such as the PI3K/AKT signalling cascade, to evade apoptosis and enhance its replication. However, the role of the PI3Kγ isoform in ZIKV‐induced neuroinflammation has not been previously explored, and this study aimed to investigate PI3Kγ in ZIKV pathogenesis. Primary neuronal cultures from PI3Kγ‐deficient mice (PI3Kγ ^kd/kd ) and human neuroblastoma SH‐SY5Y cells treated with the PI3Kγ inhibitor AS605240 were infected with ZIKV to assess the impact of PI3Kγ signalling on viral replication and neuronal survival. Additionally, interferon α/β receptor knockout (A129) mice were treated with AS605240 either before or after ZIKV infection to evaluate the pathway's role in neuroinflammation. In vitro, both genetic ablation and pharmacological inhibition of PI3Kγ suppressed ZIKV replication (~3% and ~17%, respectively) and prevented neuronal death (~16%). In vivo, mice treated with the PI3Kγ inhibitor exhibited enhanced protection against ZIKV infection, characterised by reduced viral load (~12%) and diminished brain and optic nerve damage. This neuroprotective effect correlated with reduced TNF production (about ~67%) by microglia. Furthermore, inhibition of PI3Kγ curtailed the recruitment and activation of CD8+ T cells and decreased the production of pro‐inflammatory mediators, including IFN‐γ and IL‐17, in the brains of ZIKV‐infected mice. These findings suggest that PI3Kγ activation facilitates ZIKV infection and exacerbates neuroinflammation. Pharmacological inhibition of the PI3Kγ pathway may offer therapeutic benefits by limiting viral replication and alleviating neuroinflammatory responses during ZIKV infection.

Prostate cancer (PCa) progression involves dynamic interactions between neoplastic cells and the reactive stroma (RS). Although myofibroblasts are established components of the RS, the role of other stromal populations, such as telocytes, remains poorly understood. This study investigated the presence and distribution of a telocytic stromal phenotype (CD34⁺/Vimentin⁺) in PCa across different histological grades and acinar patterns. We used digital image analysis and standardized immunohistochemistry to assess biopsy samples from 120 patients with confirmed PCa. The telocytic phenotype showed a heterogeneous distribution and was significantly enriched in high-grade tumors and specific acinar architectures, particularly Patterns B and D. In contrast, well-differentiated regions exhibited lower telocyte density, resembling non-neoplastic prostate tissue. Although the myofibroblastic phenotype (α-SMA⁺/Vimentin⁺/CD34⁻) also increased overall with tumor grade and varied across acinar patterns, this association was comparatively weaker and less statistically robust than that observed for telocytes. These results suggest that stromal remodeling encompasses a spectrum of cellular phenotypes influenced by local architectural constraints. It is proposed that telocytes serve as key mediators of tissue organization and biomechanical signaling, contributing to a feedback loop that promotes tumor progression. Combining acinar architecture with stromal phenotyping provides a refined framework for understanding epithelial–stromal co-evolution in PCa.

Exacerbated inflammation is a major contributor to tissue damage and mortality in infectious diseases, including SARS-CoV-2. The resolution phase of inflammation is critical for restoring tissue homeostasis following an injury. Annexin A1 (AnxA1) is a ubiquitous protein that plays a fundamental role in the resolution of inflammation, including in preclinical models of infectious disease. Here, we investigated the role of AnxA1 in coronavirus infection and its potential as a host-targeted therapeutic strategy against SARS-CoV-2. Wildtype (WT) and AnxA1 knockout (AnxA1KO) mice were intranasally infected with the murine betacoronavirus MHV-3 to study the endogenous role of AnxA1. Immunohistochemistry and Western blot analyses in the lungs of MHV-3-infected mice revealed increased AnxA1 expression and its cleavage, which was associated with neutrophilic infiltration (Ly6G+ cells) mainly in peribronchiolar and perivascular regions. AnxA1-deficient mice exhibited higher neutrophilic infiltration and lung damage, alongside increased CXCL1 production in the lungs, when compared with WT-infected mice. In a murine model of SARS-CoV-2 infection in K18-hACE2 mice, we found increased AnxA1 cleavage associated with lung inflammation. Treatment of SARS-CoV-2-infected K18-hACE2 mice with the AnxA1-mimetic peptide, Ac2-26, reduced lung damage and lethality, without altering the host ability to deal with viral replication. Notably, Ac2-26-treated mice exhibited similar levels of protection to that afforded by the nucleotide analog Remdesivir, following SARS-CoV-2 infection. Our findings highlight the protective role of the endogenous AnxA1 in mitigating coronavirus-induced lung inflammation and underscore the therapeutic potential of AnxA1 mimetic Ac2-26 as a host-targeted therapy against SARS-CoV-2.

Introduction: Prostate cancer (PC) remains a significant global health concern, with prognostic assessments largely reliant on the Gleason Classification System. While it has proven effective, subjectivity in interpretation persists, prompting the need for complementary approaches. Reactive stroma (RS) has emerged as a potential candidate for enhancing PC characterization, as it reflects intricate interactions among stromal, epithelial, and extracellular matrix components. To shed light on this, we conducted a comprehensive study.Methods: Two expert pathologists independently analyzed consecutive prostate biopsies (n = 120 patients), categorized into four groups based on Gleason scores. Four acinar patterns were described, denoted as A, B, C, and D. Our study uncovered a noteworthy presence of RS, predominantly within poorly differentiated tumors. Stromogenic tumors, characterized by high RS content, were particularly associated with Gleason scores of 4 + 3 and ≥ 8. Intriguingly, acinar patterns, including the distinctive B and D patterns, exhibited strong correlations with stromogenic tumors. Incorporating quantitative imaging techniques (Second Harmonic Generation and Two‐Photon Excitation Fluorescence Microscopy), we examined collagen fiber density within the stroma.Results: Our analysis revealed a direct relationship between RS intensity and collagen fiber counts, particularly prominent in patterns B and D. These findings suggest that the stromal reaction in PC is closely linked to acinar morphology and collagen deposition. Moreover, rudimentary microacini at the tumor periphery, associated with intense RS and patterns B and D, may signify an unfavorable prognosis.Conclusion: Our study highlights the potential of RS as an additional prognostic factor in PC. It underscores the intricate interplay between acinar patterns, RS intensity, and collagen fiber density, providing valuable insights for future prognostic assessments and therapeutic strategies. Further exploration of these relationships is essential for a comprehensive understanding of PC progression and management.

ARL13B is a small regulatory GTPase that controls ciliary membrane composition in both motile cilia and non-motile primary cilia. In this study, we investigated the role of ARL13B in the efferent ductules, tubules of the male reproductive tract essential to male fertility in which primary and motile cilia co-exist. We used a genetically engineered mouse model to delete Arl13b in efferent ductule epithelial cells, resulting in compromised primary and motile cilia architecture and functions. This deletion led to disturbances in reabsorptive/secretory processes and triggered an inflammatory response. The observed male reproductive phenotype showed significant variability linked to partial infertility, highlighting the importance of ARL13B in maintaining a proper physiological balance in these small ducts. These results emphasize the dual role of both motile and primary cilia functions in regulating efferent duct homeostasis, offering deeper insights into how cilia related diseases affect the male reproductive system.

The COVID-19 pandemic caused by the SARS-CoV-2 (β-CoV) betacoronavirus has posed a significant threat to global health. Despite the availability of vaccines, the virus continues to spread, and there is a need for alternative strategies to alleviate its impact. Vitamin D, a secosteroid hormone best known for its role in bone health, exhibits immunomodulatory effects in certain viral infections. Here, we have shown that bioactive vitamin D (calcitriol) limits in vitro replication of SARS-CoV-2 and murine coronaviruses MHV-3 and MHV-A59. Comparative studies involving wild-type mice intranasally infected with MHV-3, a model for studying β-CoV respiratory infections, confirmed the protective effect of vitamin D in vivo. Accordingly, mice fed a standard diet rapidly succumbed to MHV-3 infection, whereas those on a vitamin D-rich diet (10,000 IU of Vitamin D₃/kg) displayed increased resistance to acute respiratory damage and systemic complications. Consistent with these findings, the vitamin D-supplemented group exhibited lower viral titers in their lungs and reduced levels of TNF, IL-6, IL-1β, and IFN-γ, alongside an enhanced type I interferon response. Altogether, our findings suggest vitamin D supplementation ameliorates β-CoV-triggered respiratory illness and systemic complications in mice, likely via modulation of the host’s immune response to the virus.

Nonphlogistic migration of macrophages contributes to the clearance of pathogens and apoptotic cells, a critical step for the resolution of inflammation and return to homeostasis. Angiotensin-(1-7) [Ang-(1-7)] is a heptapeptide of the renin-angiotensin system that acts through Mas receptor (MasR). Ang-(1-7) has recently emerged as a novel proresolving mediator, yet Ang-(1-7) resolution mechanisms are not fully determined. Herein, Ang-(1-7) stimulated migration of human and murine monocytes/macrophages in a MasR-, CCR2-, and MEK/ERK1/2–dependent manner. Pleural injection of Ang-(1-7) promoted nonphlogistic mononuclear cell influx alongside increased levels of CCL2, IL-10, and macrophage polarization toward a regulatory phenotype. Ang-(1-7) induction of CCL2 and mononuclear cell migration was also dependent on MasR and MEK/ERK. Of note, MasR was upregulated during the resolution phase of inflammation, and its pharmacological inhibition or genetic deficiency impaired mononuclear cell recruitment during self-resolving models of LPS pleurisy and E . coli peritonitis. Inhibition/absence of MasR was associated with reduced CCL2 levels, impaired phagocytosis of bacteria, efferocytosis, and delayed resolution of inflammation. In summary, we have uncovered a potentially novel proresolving feature of Ang-(1-7), namely the recruitment of mononuclear cells favoring efferocytosis, phagocytosis, and resolution of inflammation. Mechanistically, cell migration was dependent on MasR, CCR2, and the MEK/ERK pathway.

Zika virus (ZIKV) infection of neurons leads to neurological complications and congenital malformations of the brain of neonates. To date, ZIKV mechanism of infection and pathogenesis is not entirely understood and different studies on gene regulation of ZIKV-infected cells have identified a dysregulation of inflammatory and stem cell maintenance pathways. MicroRNAs (miRNAs) are post-transcriptional regulators of cellular genes and they contribute to cell development in normal function and disease. Previous reports with integrative analyses of messenger RNAs (mRNAs) and miRNAs during ZIKV infection have not identified neurological pathway defects. We hypothesized that dysregulation of pathways involved in neurological functions will be identified by RNA profiling of ZIKV-infected fetal neurons. We therefore used microarrays to analyze gene expression levels following ZIKV infection of fetal murine neurons. We observed that the expression levels of transcription factors such as neural PAS domain protein 4 (Npas4) and of three members of the orphan nuclear receptor 4 (Nr4a) were severely decreased after viral infection. We confirmed that their downregulation was at both the mRNA level and at the protein level. The dysregulation of these transcription factors has been previously linked to aberrant neural functions and development. We next examined the miRNA expression profile in infected primary murine neurons by microarray and found that various miRNAs were dysregulated upon ZIKV infection. An integrative analysis of the differentially expressed miRNAs and mRNAs indicated that miR-7013-5p targets Nr4a3 gene. Using miRmimics, we corroborated that miR-7013-5p downregulates Nr4a3 mRNA and protein levels. Our data identify a profound dysregulation of neural transcription factors with an overexpression of miR-7013-5p that results in decreased Nr4a3 expression, likely a main contributor to ZIKV-induced neuronal dysfunction.