https://dspace.piwet.pulawy.pl/xmlui/handle/123456789/5 2026-05-27T03:45:38Z https://dspace.piwet.pulawy.pl/xmlui/handle/123456789/948 Leptospira Infections in Cats—What Do We Know? Wasiński, Bernard The incidence of Leptospira spp. infections in cats did not seem to be of major importance un- til the early 21st century. The relatively rare occurrence of individuals presenting antibodies against Leptospira spp. and the almost unheard of clinical cases appeared to suggest that felids are poorly prone to Leptospira infections. Considering the close contact of cats with rodents (mice, rats, etc.), which are the main reservoir of leptospires, the above observations may, on the one hand, be surprising, but on the other hand, may reflect species-specific biological or ecological factors influencing susceptibility, although the underlying mech- anisms remain poorly understood. The suspicions indicating cats as incidental hosts or asymptomatic carriers of Leptospira spp., their proximity to humans, and the “One Health” approach—particularly relevant recently in control of zoonoses—contributed in recent decades to greater research interest in feline leptospiral infections. Recent increasingly frequent data on the occurrence of antileptospiral antibodies in cats, cases of isolation of leptospiral DNA or viable spirochetes from blood or urine samples, and finally cases of clinical disease may support these hypotheses, although the available evidence remains limited and warrants further investigation. This review presents the current data on the incidence and pathogenesis of infections caused by Leptospira spp. in cats and their potential epidemiological role, including their possible contribution to environmental contamination and zoonotic transmission. 2026-01-01T00:00:00Z https://dspace.piwet.pulawy.pl/xmlui/handle/123456789/947 Natural polymorphisms in the bovine leukemia virus microRNA cluster modulate miRNA expression and host regulatory pathways Pluta, Aneta; Skovgaard, Kerstin; Dębski, Konrad Józef; Peloponese, Jean Marie; Sokacz, Madison; Mourouvin, Celima; Taxis, Tasia Marie Bovine leukemia virus (BLV) encodes a cluster of viral microRNAs (miRNAs) that remain abundantly expressed dur- ing latency, when viral protein production is restricted. Naturally occurring single-nucleotide polymorphisms (SNPs) within this locus are common, yet their functional consequences for miRNA output and host gene regulation remain poorly defined. Peripheral blood leukocytes from 53 naturally BLV-infected cattle were analyzed, and the 554-nt BLV miRNA locus was amplified and sequenced. Field-derived variants containing mutations within RNA polymerase III promoter motifs, seed regions, and termination signals were selected for functional evaluation. Reference and vari- ant loci were co-expressed with a BLVΔ-miRNA infectious clone in HEK293T cells under controlled conditions. Mature miRNA levels were quantified by stem-loop reverse-transcription quantitative polymerase chain reaction (RT–qPCR), and global host transcriptional responses were assessed using oligonucleotide microarrays. Predicted miRNA targets were identified using bioinformatic analyses. Sequence analysis identified 84 polymorphic sites, with a substantial proportion mapping to Pol III regulatory elements and seed regions. Variant loci displayed altered accumulation of selected mature miRNAs and shifts in predicted seed-dependent target repertoires. Transcriptome profiling revealed variant-associated modulation of innate immune-signaling components, interferon-responsive genes, antigen-presentation pathways, tumor-suppressor networks, and extracellular matrix-related processes. Enrichment analysis demonstrated a statistically significant overlap between predicted miRNA targets and downregulated tran- scripts. Natural polymorphisms within the BLV miRNA cluster modulate miRNA expression and are associated with dis- tinct host regulatory signatures in a controlled experimental system. These findings suggest that sequence variation in the viral miRNA locus may contribute to differential host–virus interactions and influence mechanisms supporting viral persistence. 2026-01-01T00:00:00Z https://dspace.piwet.pulawy.pl/xmlui/handle/123456789/946 Valproate reactivates HTLV-1 tax and reduces ABCB1/MDR1 expression in PBMCs derived from ATLL patients Mourouvin, Celima; Tram, Julie; Marty, Laetitia; Marie-Delcasse, Anika; Belrose, Gildas; Pluta, Aneta; Cesaire, Raymond; Helias, Phillipe; Baccini, Veronique; Peloponese Jr., Jean-Marie Chemoresistance remains a major obstacle to effective treatment and durable remission in leukemia patients. Although initial responses to chemotherapy are often favorable, relapse frequently occurs due to the emergence of drug-resistant malignant clones. Resistance mechanisms may be intrinsic or acquired and involve drug efflux, impaired apoptosis, enhanced DNA repair, epigenetic alterations, dysregulated signaling pathways, and microenvironmental interactions. A central mediator of multidrug resistance is the ATP-binding cassette (ABC) transporter family, particularly ABCB1 (also known as P- glycoprotein or MDR-1), which actively exports chemotherapeutic agents such as etoposide, doxorubicin, and vincristine, thereby reducing intracellular drug accumulation. Adult T-cell Leukemia/Lymphoma (ATLL), an aggressive malignancy caused by Human T-cell Leukemia Virus type 1 (HTLV-1), is characterized by poor prognosis and marked resistance to chemotherapy. Despite the recent approval of novel therapeutic agents, treatment outcomes remain unsatisfactory, largely due to both inherent and acquired chemoresistance. Overexpression of ABCB1 has been identified as a key mechanism contributing to multidrug resistance in ATLL. We compared the expression profiles of ABC transporter genes in CD8⁺-depleted peripheral blood mononuclear cells (PBMCs) from HTLV-1 asymptomatic carriers and patients with acute ATLL. To investigate the role of the viral transactivator Tax in regulating ABCB1 expression, we used HuT78 and JPX9 T-cell lines. Furthermore, Tax expression was reactivated in CD8⁺-depleted PBMCs from acute ATLL patients using valproic acid, and subsequent changes in ABCB1 expression and chemosensitivity to etoposide and doxorubicin were assessed. We found that ABCB1 expression was significantly upregulated in CD8⁺-depleted PBMCs from patients with acute ATLL compared to asymptomatic HTLV-1 carriers. In contrast, expression of the viral protein Tax in HuT78 and JPX9 cell lines resulted in decreased ABCB1 levels. Reactivation of Tax expression using valproic acid in primary ATLL samples confirmed that Tax downregulates ABCB1 expression. Importantly, Tax reactivation restored sensitivity of ATLL cells to Frontiers in Oncology frontiersin.org01 OPEN ACCESS EDITED BY Beatrice Macchi, University of Rome Tor Vergata, Italy REVIEWED BY Saber Soltani, Tehran University of Medical Sciences, Iran Ankit Tanwar, Albert Einstein College of Medicine, United States *CORRESPONDENCE Jean-Marie Peloponese Jr. jean-marie.peloponese@ umontpellier.fr †PRESENT ADDRESS Raymond Ce´ saire, PCCEI Inserm - Universite´ des Antilles, Pointe-à-Pitre, France RECEIVED 09 October 2025 REVISED 03 February 2026 ACCEPTED 18 February 2026 PUBLISHED 12 March 2026 CITATION Mourouvin C, Tram J, Marty L, Marie-Delcasse A, Belrose G, Pluta A, Ce´ saire R, He´ lias P, Baccini V and Peloponese J-M Jr. (2026) Valproate reactivates HTLV-1 tax and reduces ABCB1/MDR1 expression in PBMCs derived from ATLL patients. Front. Oncol. 16:1721313. doi: 10.3389/fonc.2026.1721313 COPYRIGHT © 2026 Mourouvin, Tram, Marty, Marie- Delcasse, Belrose, Pluta, Ce´ saire, He´ lias, Baccini and Peloponese. This is an open- access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. TYPE Original Research PUBLISHED 12 March 2026 DOI 10.3389/fonc.2026.1721313 chemotherapeutic agents, including etoposide and doxorubicin. Our findings identify ABCB1 overexpression as a major contributor to chemoresistance in acute ATLL and demonstrate that the viral protein Tax negatively regulates ABCB1 expression. These results suggest that reactivation of Tax may reduce drug efflux capacity and restore chemosensitivity in resistant ATLL cells. Collectively, this study provides a rationale for exploring a “Tax-based shock- andkill” strategy as a potential therapeutic approach to overcome chemoresistance in ATLL. 2026-01-01T00:00:00Z https://dspace.piwet.pulawy.pl/xmlui/handle/123456789/945 The effect of allicin on the intestinal microbiota and production efficiency in selected farm animals Jarosz, Aleksandra; Drabik, Kamil; Domaradzki, Piotr; Sapała, Magdalena; Ziomek, Monika; Batkowska, Justyna; Grenda, Tomasz Allicin is a sulphur-containing bioactive compound naturally synthesised in several Allium species, including white garlic (Allium sativum L.), bear garlic (Allium ursinum L.) and field garlic (Allium vineale L.). Current literature indicates that allicin exhibits a wide range of therapeutic activities, most notably antimicrobial, antiparasitic, antioxidant, antiviral and antifungal effects. Its biological action is primarily driven by two key mechanisms: rapid penetration into pathogenic cells and the induction of lethal intracellular alterations. The breadth of allicin’s biological properties has prompted growing interest in its potential applications in the livestock industry. Dietary supplementation with allicin has been associated with improved growth performance, enhanced immune function, better quality of animal-derived products and favourable modulation of the intestinal microbiota – an aspect of particular relevance because of the central role of gut microorganisms in animal health. The aim of this review is to summarise current knowledge on the biological properties of allicin, and to particularly consider its effects on intestinal microbial modulation and its potential to improve the production efficiency of livestock. 2026-01-01T00:00:00Z