The tropical horse tick, Dermacentor nitens, is a one-host hard tick widely distributed across tropical and subtropical regions of the Americas, where it primarily parasitizes horses and occasionally cattle and other livestock. This species is of veterinary importance due to its role as a vector of Babesia caballi, the causative agent of equine piroplasmosis. Despite its significance, genomic resources for D. nitens remain scarce, limiting molecular and functional studies. Here, we present the most comprehensive transcriptome assembly of D. nitens to date, encompassing midgut and ovary transcriptomes during the rapid phase of blood feeding. Using deep sequencing approaches, we identified and annotated a large repertoire of transcripts expressed during blood feeding and reproduction, processes central to tick survival and pathogen transmission. To further facilitate gene discovery in D. nitens, we conducted orthology searches against annotated transcripts from the genomes of Dermacentor albipictus, Dermacentor andersoni, Dermacentor silvarum, Dermacentor variabilis, Hyaloma asiaticum, Haemaphysalis longicornis, Ixodes scapularis, Ixodes persulcatus, Rhipicephalus microplus, and Rhipicephalus sanguineus. Our dataset provides new insights into midgut and ovary physiology, including genes associated with blood meal digestion and oogenesis, which are critical for reproduction and life cycle progression. These findings expand the molecular toolkit available for D. nitens, enabling future studies on tick physiology, evolution, and vector competence. Moreover, this resource offers a framework for comparative analyses with other Dermacentor species of medical relevance, thereby advancing our understanding of conserved biological mechanisms underlying feeding, reproduction, and pathogen transmission.

Ticks transmit a wide range of pathogens to humans. During blood feeding, they inject salivary proteins that suppress host immune responses, enabling prolonged feeding and pathogen transmission. A hallmark of this process is the dynamic reprogramming of salivary gene expression, known as the sialome switch. Here, we describe a previously unrecognized cellular mechanism underlying this phenomenon in two medically important tick species. Using integrated multi-omics and imaging approaches, we identified a conserved population of undifferentiated salivary gland precursor cells in unfed ticks. Upon host attachment, these precursors undergo terminal differentiation into specialized secretory subtypes through a conserved transcriptional and signaling framework that drives salivary gland activation and maturation. Unlike other blood-feeding arthropods, tick salivary glands dynamically remodel in response to host contact, producing saliva with a shifting composition. This study suggests the cellular basis of adult female tick salivary gland maturation and offers targets to disrupt feeding and pathogen transmission.

Horizontal transfer of transposable elements (TEs) is widespread in eukaryotes, driving genetic variation and often associated with bursts of TE activity. Here, we report a recent TE burst in the insect-pathogenic fungus Metarhizium anisopliae. The actively transposing TEs were likely introduced via hitchhiking on a so-called Starship, a class of large, horizontally transferable transposons. This TE burst likely triggered extensive structural reshuffling across all chromosomes, which was associated with loss of pathogenicity. Expanding our analysis to other fungi, we found that Starship-mediated horizontal transfer of TEs is a general phenomenon. Most (75%) of 522 reported Starships harbor TEs; many of which show evidence of a recent burst, in some cases likely starting from the TE copies on the Starship itself. A high fraction of TEs located on Starships also shows signatures of past horizontal transfer. Collectively, our results establish Starships as major vectors of horizontal TE transfer.

Horizontal transfer (HT) of transposable elements (TEs) is a widespread phenomenon in eukaryotes and is often associated with bursts of TE activity. This process profoundly influences genome evolution by introducing novel genetic material and driving genetic variation. However, the precise mechanisms facilitating these transfers remain largely uncharacterized. Here, we report a recent TE burst in the insect-pathogenic fungus Metarhizium anisopliae . Our analysis reveals that the actively transposing TEs were introduced via hitchhiking on a so-called Starship—a class of large, themselves horizontally transferable transposons found within the fungal subphylum Pezizomycotina . This particular Starship carried 73 TEs, 43 of which exhibited increased copy numbers in the recipient genome, including 508 perfect copies. This expansion triggered extensive structural reshuffling across all chromosomes and led to the formation of a novel chromosome. Remarkably, this structural reorganization was associated with a dramatic phenotypic shift: the loss of pathogenicity. Expanding our analysis to other fungi, we found that Starship-mediated horizontal transfer of TEs is a general phenomenon. A majority (74%) of 618 published Starships also harbor TEs, which can constitute up to 72% of their content. Moreover, Starships serve as sources of actively transposing TEs: 16% of Starships carried at least one TE with a perfect copy found elsewhere in the genome, and identical TEs were observed on Starships from different species. Collectively, our results establish Starships as major vectors of horizontal TE transfer within Pezizomycotina and further highlight their profound impact on recipient fungal genomes through TE piggybacking. ### Competing Interest Statement The authors have declared no competing interest. The sequencing reads, genome assemblies of M. anisopliae strain NE and strain E6 were deposited on NCBI using the bioproject PRJNA1277033 and PRJNA1277034.

The Zika virus (ZIKV) has been associated with neurological and cardiovascular complications, including myocarditis, arrhythmias and thrombotic events. This study evaluated the thrombotic and oxidative responses induced by ZIKV in cardiac cells and immunocompetent mice. Cardiac (H9c2) and vascular smooth muscle (A7r5) cell lines were infected with ZIKV and analyzed for viral replication, cytopathic effects and oxidative stress. In vivo, female FVB/N mice were inoculated with ZIKV and cardiac tissue was analyzed for markers of myocardial damage, prothrombotic enzymes and oxidative stress. H9c2 cells demonstrated higher viral replication and cytopathic effects than A7r5 cells. ZIKV-infected cells exhibited increased lactate dehydrogenase release and oxidative stress markers, including elevated protein carbonylation and reactive oxygen species. In vivo, infected mice displayed significant increases in cardiac troponin T levels, indicative of myocardial injury. Analysis of cardiac tissue revealed elevated thrombin and Factor Xa activities and reduced plasmin, indicating a prothrombotic state. Oxidative stress was marked by increased activities of antioxidant enzymes (GPx, SOD) and reduced glutathione levels, alongside heightened protein oxidation. This study demonstrates that ZIKV infection disrupts cardiovascular homeostasis by inducing myocardial injury, prothrombotic state and oxidative stress. These findings underscore the potential of ZIKV to affect the cardiovascular system beyond its established neurotropism, highlighting the need for further investigation into its systemic impacts.

Ixodes scapularis is a primary vector of several important tick-borne pathogens including Borrelia burgdorferi sensu lato, the causative bacterial genospecies complex of Lyme disease, Babesia microti, Anaplasma phagocytophilum, Borrelia miyamotoi, Ehrlichia muris eauclarensis, and Powassan virus. Salivary compounds secreted by I. scapularis during blood feeding are immunogenic and can elicit robust antibody responses in humans which can potentially be leveraged as surrogate markers of prior tick bite exposure. In this study, we investigate the potential of a tick secreted salivary serine protease inhibitor, IxsS7, as a novel antigenic biomarker of I. scapularis exposure in humans. We demonstrate that the IxsS7 protein-coding sequence is highly conserved (>90 % identity) among other important Ixodes species (e.g., Ixodes ricinus, Ixodes persulcatus, and Ixodes pacificus) and poorly conserved (<50 % identity) with homologs from other tick genera, such as Amblyomma spp., Dermacentor spp., Rhipicephalus spp., and Haemaphysalis spp. Antibodies in sera from rabbits immunized with recombinant IxsS7 (rIxsS7) strongly recognize native IxsS7 when challenged with salivary gland homogenate (SGH) from blood-fed I. scapularis females, while showing minimal cross-reactivity with SGH from other hard tick (Ixodidae) genera. Western blot and ELISA analyses revealed that human subjects who reported recent prior exposure to ticks possessed IgG antibodies that recognized rIxsS7, highlighting its potential as a biomarker of exposure specifically against I. scapularis. Further development of serological tools that can measure human antibody responses to Ixodes-specific salivary antigens is essential to better quantify individual- and population-level risk of important tick-borne diseases such as Lyme disease.

The Zika Virus (ZIKV) is a Flavivirus that caused a recent outbreak worldwide resulting in different neurological outcomes that are still poorly characterized and understood. Concerning this issue, in vitro and in vivo models are being applied to improve the molecular understanding of ZIKV infection. In this work, applying shotgun proteomics we revealed the differential ZIKV infection proteome in Vero cells, a non-neural cell model. A dramatic change resulting from infection was found including the differential expression of several proteins previously associated with brain diseases. The molecular alterations caused by this pathogen were further characterized through bioinformatics such as Gene Ontology and protein-protein interaction network of resulting differential proteome. Our findings identified molecular markers that were differentially expressed during ZIKV infection and had been previously linked to neurological conditions and infections caused by ZIKV and/or SARS-CoV-2. The results presented in this article highlight molecular markers associated with neurological dysfunctions, demonstrating that ZIKV infection can dysregulate neural-specific genes, even in non-neural cells.

Ticks obtain a blood meal by lacerating small blood vessels and ingesting the blood that flows to the feeding site, which triggers various host responses. However, ticks face the challenge of wound healing, a process involving hemostasis, inflammation, cell proliferation and migration, and remodeling, hindering blood acquisition. To overcome these obstacles, tick salivary glands produce an array of bioactive molecules. Here, we characterize ixochymostatin, an Ixodes scapularis protein belonging to the trypsin inhibitor-like (TIL) family. It is expressed in multiple developmental stages and in tick salivary glands and acts as a slow and tight-binding inhibitor of chymase, cathepsin G, and chymotrypsin. Predictions for the tertiary structure complex between ixochymostatin and chymase suggest a direct interaction between the inhibitor reactive site loop and protease active sites. In vitro, ixochymostatin protects the endothelial cell barrier against chymase degrading action, decreasing cell permeability. In vivo, it reduces vascular permeability induced by chymase and compound 48/80, a mast cell degranulator agonist, in a mouse model. Additionally, ixochymostatin inhibits the chymase-dependent generation of vasoconstrictor peptides. Antibodies against ixochymostatin neutralize its inhibitory properties, with epitope mapping identifying potential neutralization regions. Ixochymostatin emerges as a novel tick protein modulating host responses against tick feeding, facilitating blood acquisition.

Baccharis articulata (Lam) Pers. is an herb native to southern Brazil and is widely used in local traditional medicine for weight loss and for the treatment of digestive and liver diseases. However, only a few studies have been conducted to scientifically validate the folk use of this plant. This study assessed the in vitro therapeutic effects of an aqueous extract of B. articulata and chlorogenic acid on liver fibrosis in murine hepatic stellate cells (HSC; GRX cell line). The decrease in cell proliferation and cytotoxicity, as well as phenotypic reversion by the presence of lipid droplets and reduction in collagen content after seven days of treatment, were evaluated. The mechanisms responsible for the antifibrotic effects of the extract, including the plasminogen activation system, were assessed. from high-performance liquid chromatography coupled with diode array detector and tandem mass spectrometry (HPLC-DAD-MS/MS) data. Twenty-six metabolites were identified in the extract, including flavonoids, phenylpropanoid derivatives, and diterpenes. Treatment with the extract significantly induced the accumulation of lipids in the cytoplasm of cells, indicating that it could revert the HSC phenotype to a quiescent state with no cytotoxic or antiproliferative effects. These findings may be related to the inhibition of the TGF-β1 pathway, a biomarker of liver fibrosis, upregulation of the plasminogen system, and dose-dependent inhibition of plasmin activity. The presence of caffeoylquinic acids seems to be partially related to the extract effect, as chlorogenic acid displayed antiproliferative activity and reduced collagen content in hepatic stellate cells. Considering the unmet need for antifibrotic therapies, the use of medicinal plants to inhibit the proliferation of activated HSC is promising, and this study indicated that the aqueous extract of B. articulata has potential therapeutic activity against hepatic fibrosis (see also Figure 1(Fig. 1) graphical abstract).

The pathophysiology of recurrent pregnancy loss (RPL) involves deficiencies in the proliferation and migration capacities of endometrial stromal cells (hESCs), which impair embryo implantation and development. Since animal venoms are rich source of bioactive molecules, we aimed to characterize the cytoprotective effects of Lonomia obliqua venom on hESCs. hESCs were isolated from endometrial biopsies and the mechanisms of L. obliqua venomous secretions on cell viability, proliferation and migration were characterized. Venom components were identified by chromatography and proteomic analyses. L. obliqua venom induced hESC proliferation, viability and migration in a dose-dependent manner, both in the presence and absence of serum. By ion-exchange chromatography, one fraction enriched in cytoprotective components and devoid of hemotoxins was obtained. Venom proteome identified at least six protein classes with potential cytoprotective properties (hemolins, lipocalins, hemocyannins, antiviral proteins, antimicrobial peptides, and protease inhibitors). L. obliqua venom protected hESCs from oxidative insult. Cytoprotection was also related to nitric oxide and PKC-ERK-activation and down-regulation of cAMP-PKA-dependent pathways that control cell proliferation. L. obliqua venom-induced hESC viability, proliferation and migration occurs mainly by protecting against oxidative damage and activating ERK. Thus, L. obliqua venom components are promising pharmacological tools to understand the underlying mechanisms of hESC deficiency in RPL.

Blood-feeding behavior has independently evolved in arthropods multiple times. Unlike hard ticks, soft ticks employ a rapid-feeding strategy for hematophagy, and there are comparatively limited studies on the transcriptomes of these organisms. This study investigates the soft tick Ornithodoros hermsi, conducting histopathological examinations at bitten skin sites and tick whole-body transcriptomic analyses across various developmental and feeding stages, including larvae, 1st-nymphal, and 2nd-nymphal stages. The results revealed the ability of O. hermsi to induce skin hemorrhage at the bite sites. Transcriptomic analyses identified three consistent transcriptional profiles: unfed, early-fed (6 h, 12 h, 24 h), and late-fed (5 days). The unfed profile exhibited high transcriptional activity across most of the functional classes annotated. In contrast, early-fed stages exhibited decreased expression of most functional classes, except for the unknown, which is highly expressed. Finally, transcriptional expression of most functional classes increased in the late-fed groups, resembling the baseline expression observed in the unfed groups. These findings highlight intense pre-feeding transcriptional activity in O. hermsi ticks, aligning with their rapid-feeding strategy. Moreover, besides shedding light on the temporal dynamics of key pathways during blood meal processing and tick development, this study contributes significantly to the transcriptome repertoire of a medically relevant soft tick species with relatively limited prior knowledge.

The pivotal role of human endometrial stromal cells (hESCs) in the development of endometriosis lies in their ability to adopt a pro-invasive and proinflammatory profile upon migration to areas outside the uterus. However, the molecular mechanisms involved in these events remain unclear. In this study, we investigated how angiotensin II (Ang II) affects the plasminogen-plasmin system in hESCs, and the mechanisms underlying cell proliferation, migration, matrix degradation, and inflammation. Precursors, receptors, and peptidases involved in angiotensin metabolism increased significantly in Ang II-treated hESCs. The expression and activity of tissue (tPA)- and urokinase (uPA)- type plasminogen activators and the receptor for uPA (uPAR) were induced in the presence of Ang II. The up-regulation of tPA-uPA/uPAR pathway significantly contributes to heightened plasmin production both on the surface of hESCs and in their conditioned media. As a result, the plasmin generation induced by Ang II enhances the degradation of fibrin and matrix proteins, while also boosting hESC viability, proliferation, and migration through the up-regulation of growth factor expression. Notably, Ang II-induced hESC migration was dependent on the generation of active plasmin on cell surface. Ang II regulates oxidative and inflammatory signalling in hESCs primarily via NADPH oxidase and through the up-regulation of proinflammatory cytokines and adhesion molecules. Interestingly, Ang II receptor (AT1R) blockage, decreased plasmin generation, tPA-uPA/uPAR expression and hESC migration. Our results suggest that Ang II/AT1R axis regulates hESC proliferation and migration through tPA-uPA/uPAR pathway activation and plasmin generation. We propose the Ang II/AT1R axis as a potential target for endometriosis treatment.

The aim of this study was to identify, using proteomics, the molecular alterations caused by human serum exposure to Klebsiella pneumoniae ACH2. The analysis was performed under two different conditions, native serum from healthy donors and heat-inactivated serum (to inactivate the complement system), and at two different times, after 1 and 4 h of serum exposure. More than 1,000 bacterial proteins were identified at each time point. Enterobactin, a siderophore involved in iron uptake, and proteins involved in translation were upregulated at 1 h, while the chaperone ProQ and the glyoxylate cycle were identified after 4 h. Enzymes involved in the stress response were downregulated, and the SOD activity was validated using an enzymatic assay. In addition, an intricate metabolic adaptation was observed, with pyruvate and thiamine possibly involved in survival and virulence in the first hour of serum exposure. The addition of exogenous thiamine contributes to bacterial growth in human serum, corroborating this result. During 4 h of serum exposure, the glyoxylate cycle (GC) probably plays a central role, and the addition of exogenous succinate suppresses the GC, inducing a decrease in serum resistance. Therefore, serum exposure causes important changes in iron acquisition, the expression of virulence factors, and metabolic reprogramming, which could contribute to bacterial serum resistance.

A strict correlation among proximal tubule epithelial cell dysfunction, proteinuria, and modulation of the Renin-Angiotensin System and Kalikrein-Kinin System are crucial factors in the pathogenesis of Acute Kidney Injury (AKI). In this study, we investigated the potential protective effect of preconditioning by moderate-intensity aerobic exercise on gentamicin-induced AKI. Male Wistar rats were submitted to a moderate-intensity treadmill exercise protocol for 8 weeks, and then injected with 80 mg/kg/day s.c. gentamicin for 5 consecutive days. Four groups were generated: 1) NT+SAL (control); 2) NT+AKI (non-trained with AKI); 3) T+SAL (trained); and 4) T+AKI (trained with AKI). The NT+AKI group presented: 1) impairment in glomerular function parameters; 2) increased fractional excretion of Na + , K + , and water; 4) proteinuria and increased urinary gamma-glutamyl transferase activity (a marker of tubular injury) accompanied by acute tubular necrosis; 5) an increased renal angiotensin-converting enzyme and bradykinin B1 receptor mRNA expression. Interestingly, the preconditioning by moderate-intensity aerobic exercise attenuated all alterations observed in gentamicin-induced AKI (T+AKI group). Taken together, our results show that the preconditioning by moderate-intensity aerobic exercise ameliorates the development of gentamicin-induced AKI. Our findings help to expand the current knowledge regarding the effect of physical exercise on kidneys during physiological and pathological conditions.

Cryptococcus gattii is a primary pathogenic fungus that causes pneumonia. This species is also responsible for an outbreak in Vancouver, Canada, and spreading to the mainland and United States. The use of medical devices is often complicated by infections with biofilm-forming microbes with increased resistance to antimicrobial agents and host defense mechanisms. This study investigated the comparative proteome of C. gattii R265 (VGIIa) grown under planktonic and biofilm conditions. A brief comparison with C. neoformans H99 biofilm and the use of different culture medium and surface were also evaluated. Using Multidimensional Protein Identification Technology (MudPIT), 1819 proteins were identified for both conditions, where 150 (8.2%) were considered differentially regulated (up- or down-regulated and unique in biofilm cells). Overall, the proteomic approach suggests that C. gattii R265 biofilm cells are maintained by the induction of electron transport chain for reoxidation, and by alternative energy metabolites, such as succinate and acetate. SIGNIFICANCE: Since C. gattii is considered a primary pathogen and is one of the most virulent and less susceptible to antifungals, understanding how biofilms are maintained is fundamental to search for new targets to control this important mode of growth that is difficult to eradicate.