Silvia Guzmán-Beltrán

Severe Influenza A virus (IAV) infection is associated with endothelial dysfunction, inflammation, and coagulation abnormalities. However, the mechanisms linking endothelial inflammatory activation to thrombosis remain incompletely understood. We investigated whether Influenza A/H1N1 induces an immunothrombotic phenotype in human brain microvascular endothelial cells. We infected HBEC-5i cells with Influenza A/H1N1 pdm09. We assessed viral infection by RT-qPCR detection of matrix (M) transcripts and by immunoblotting for the M1 protein. We evaluated endothelial responses by measuring TNF-α expression and secretion, Tissue Factor (TF) expression, TF-dependent factor Xa generation, and responses to recombinant TNF-α and thrombin. H1N1 infection increased TNF-α expression and secretion and enhanced TF expression and functional activity, indicating acquisition of a procoagulant endothelial phenotype. Recombinant TNF-α reproduced infection-associated TF induction, whereas thrombin enhanced TNF-α production and TF activity, supporting reciprocal amplification between inflammatory and coagulation pathways. These findings support a TNF-α–TF–thrombin feed-forward signaling circuit linking endothelial inflammation and coagulation during H1N1 infection. Influenza A/H1N1 induces an immunothrombotic phenotype in human brain microvascular endothelial cells, identifying this signaling axis as a potential mechanistic target for influenza-associated vascular and thrombotic complications.

Severe Influenza A virus (IAV) infection is associated with endothelial dysfunction, inflammation, and coagulation abnormalities. However, the mechanisms linking endothelial inflammatory activation to thrombosis remain incompletely understood. We investigated whether Influenza A/H1N1 induces an immunothrombotic phenotype in human brain microvascular endothelial cells. We infected HBEC-5i cells with Influenza A/H1N1 pdm09. We assessed viral infection by RT-qPCR detection of matrix (M) transcripts and by immunoblotting for the M1 protein. We evaluated endothelial responses by measuring TNF-α expression and secretion, Tissue Factor (TF) expression, TF-dependent factor Xa generation, and responses to recombinant TNF-α and thrombin. H1N1 infection increased TNF-α expression and secretion and enhanced TF expression and functional activity, indicating acquisition of a procoagulant endothelial phenotype. Recombinant TNF-α reproduced infection-associated TF induction, whereas thrombin enhanced TNF-α production and TF activity, supporting reciprocal amplification between inflammatory and coagulation pathways. These findings support a TNF-α–TF–thrombin feed-forward signaling circuit linking endothelial inflammation and coagulation during H1N1 infection. Influenza A/H1N1 induces an immunothrombotic phenotype in human brain microvascular endothelial cells, identifying this signaling axis as a potential mechanistic target for influenza-associated vascular and thrombotic complications.

Poor adherence to prolonged antibiotic regimens remains a major challenge in the treatment and prevention of chronic infectious diseases such as tuberculosis. Transdermal drug delivery systems capable of sustained antibiotic release may improve therapeutic compliance while reducing the need for frequent oral administration. In this study, electrospun polymeric membranes based on poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL) were developed as transdermal rifampicin delivery platforms. Homogeneous nanofibrous membranes with average fiber diameters of approximately 250 nm were successfully fabricated and exhibited efficient drug incorporation while preserving the structural integrity of the polymeric matrix. The electrospun membranes retained sufficient tensile strength and dimensional stability after accelerated temperature–humidity aging, supporting their stability during storage, handling, and application. In vitro cytotoxicity and biocompatibility assays using primary human peripheral blood mononuclear cells (PBMCs) demonstrated that the developed systems did not induce significant cytotoxic or pro-inflammatory responses. Transdermal permeation studies using an in vitro mouse skin model demonstrated sustained rifampicin diffusion for at least 72 h. Importantly, the antibiotic recovered after skin permeation preserved antimycobacterial activity against Mycobacterium tuberculosis H37Ra and Mycobacterium bovis BCG, confirming that rifampicin maintained its biological functionality after electrospinning and transdermal migration. Overall, these findings demonstrate the potential of electrospun PLA/PCL membranes as stable and biocompatible transdermal antibiotic delivery systems capable of sustained release and preservation of antimicrobial activity. This proof-of-concept study supports the translational potential of electrospun polymeric platforms for controlled antibiotic delivery in long-term infectious disease therapies.

This study explores the role of human visceral white adipocytes (hv-WAD) in latent tuberculosis infection (LTBI). While granulomas and macrophages are traditionally viewed as central to TB latency, emerging evidence highlights adipocytes as significant non-canonical host cells that may facilitate bacterial persistence by providing a protective niche. Unlike the immune-driven environment within granulomas, adipocytes can shield Mycobacterium tuberculosis (Mtb) from immune surveillance, promoting survival. In vitro experiments showed that Mtb invades approximately 39% of hv-WAD within 48–72 h post-infection (hpi). Both avirulent H37Ra and virulent H37Rv Mtb strains, when infecting adipocytes, expressed RNA for key virulence factors (19 kDa, 30 kDa, Ag85b, 5KST, CFP10, and ESAT6) and dormancy-associated genes (Icl1, LipY, WhiB3, SodA, and Tgs1) at 72 hpi. Infection stimulated the production of inflammatory cytokines, notably leading to a fivefold increase in TNF-α with H37Rv (p < 0.01). Additionally, we detected Mtb RNA transcripts (IS6110, 5KST, 30 kDa, CFP10, Ag85) in 68% of biopsies from TB asymptomatic patients. The transcripts suggest a metabolically heterogeneous state of mycobacteria. These findings position visceral fat as a potential reservoir for Mtb in latent TB infection and underscore the development of novel diagnostic strategies targeting adipose tissue.

Bacterial lysates have emerged as promising immunomodulatory agents that can enhance innate immune responses. Given the crucial role of macrophages in recognizing and controlling intracellular pathogens such as Mycobacterium tuberculosis, this study aimed to evaluate the immunological effects of selected bacterial lysates on human monocyte-derived macrophages (MDMs). We examined the ability of commercial bacterial lysates, Pulmonarom, Ismigen, Uro-Vaxom, and a lysate of M. tuberculosis H37 Ra (LMtb) to stimulate the production of key pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-8. In addition, we investigated whether these lysates could modulate the expression of bactericidal/permeability-increasing protein (BPI), a critical antimicrobial effector, and assessed their ability to reduce the intracellular burden of mycobacteria and induce autophagy. The results demonstrate diverse immunostimulatory profiles among the lysates, highlighting differences in both inflammatory and antimicrobial responses that may be relevant for host-directed therapeutic strategies against tuberculosis. Notably, beyond the in vitro antimycobacterial activity observed for BPI, this protein was also found to be elevated in both serum and bronchoalveolar lavage fluid from patients with active TB, reflecting local and systemic immune activation. Furthermore, the reduction in BPI levels after treatment suggests its potential utility for following the dynamics of infection.

Tuberculosis (TB) is one of the most common respiratory infections worldwide, and it is caused by Mycobacterium tuberculosis (Mtb). Mtb employs immune evasion mechanisms that allow the disease to become chronic. Despite extensive research, the host–pathogen interaction remains incompletely understood. Extracellular vesicles (EVs) are small membrane particles that play a regulatory role in infectious diseases. Host-derived EVs have been identified as carriers of proteins, messenger RNA, and lipids from both the host cells and the pathogens. In this study, we assessed the cargo of EVs in human macrophages infected with the virulent strain H37Rv of Mtb at 1 and 24 h post-infection (hpi). The results showed that 1 hpi, infected macrophages secreted EVs containing Mtb proteins (15 to 37 kDa) and Ag85 kDa, as well as RNA transcripts (ESAT-6, 5KST, Ag85, IS6110, 30 kDa, 19 kDa, and MPT64). However, these decreased at 24 hpi. The infection of macrophages with Mtb was observed to result in the release of EVs containing Ag85 protein and RNA transcripts of Mtb; this process appeared to diminish after 24 hpi, suggesting the existence of an evasion mechanism. Both Ag85 and the RNA transcripts could be potential biomarkers for the diagnosis of TB patients.

Viral RNA and miRNAs released by immune cells contribute to inflammation in COVID-19 patients. Here, we investigated the role of SARS-CoV2 RNA and host miRNAs carried within extracellular vesicles (EVs) in modulating inflammation. EVs were classified as positive or negative depending on their viral RNA cargo. To assess the function of viral RNA, EVs, and lipopolysaccharide (LPS) were used to stimulate whole blood samples from healthy subjects, and the secretion of 27 serum analytes was measured. EVs alone did not induce cytokines, chemokines, or growth factors. However, under LPS stimulation, (SARS-CoV2+) EVs increased IL-12 and decreased IL-13 secretion, while (SARS-CoV2−) EVs increased MIP-1α and IL-1β secretion. Host miR-19a-3p, -192-5p, -let-7c-5p, and -92b-3a were differentially expressed in association with viral RNA. EVs from COVID-19 patients exhibited differences in viral RNA and miRNA expression profiles that modulate LPS responses. This knowledge sheds light on the immunopathology of COVID-19.

Bactericidal permeability-increasing protein (BPI) is a multifunctional cationic protein produced by neutrophils, eosinophils, fibroblasts, and macrophages with antibacterial anti-inflammatory properties. In the context of Gram-negative infection, BPI kills bacteria, neutralizes the endotoxic activity of lipopolysaccharides (LPSs), and, thus, avoids immune hyperactivation. Interestingly, BPI increases in patients with Gram-positive meningitis, interacts with lipopeptides and lipoteichoic acids of Gram-positive bacteria, and significantly enhances the immune response in peripheral blood mononuclear cells. We evaluated the antimycobacterial and immunoregulatory properties of BPI in human macrophages infected with Mycobacterium tuberculosis. Our results showed that recombinant BPI entered macrophages, significantly reduced the intracellular growth of M. tuberculosis, and inhibited the production of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-α). Furthermore, BPI decreased bacterial growth directly in vitro. These data suggest that BPI has direct and indirect bactericidal effects inhibiting bacterial growth and potentiating the immune response in human macrophages and support that this new protein’s broad-spectrum antibacterial activity has the potential for fighting tuberculosis.