Search Results (6,103)

Background: Aminoacyl-tRNA synthetases (ARSs) are a group of enzymes responsible for the first step of protein translation. Among them, the KARS1 gene encodes lysyl-tRNA synthetase 1, an enzyme essential for charging tRNA-Lys with lysine in both the cytoplasm and mitochondria. Mutations in KARS1 are associated with a wide range of clinical phenotypes, including leukoencephalopathy, hereditary deafness, peripheral neuropathies, and multisystemic involvement. Methods: We hereby report a detailed case study of a 15-month-old boy presenting at age 5 months with developmental delay, microcephaly, hypotonia, sensorineural deafness, retinopathy, visual impairment, nystagmoid eye movements, and hepatic and immuno-hematological abnormalities. In addition, he exhibited a severe hyperkinetic movement disorder, not previously reported in the literature, and developed epilepsy at 13 months. Genetic testing identified two rare compound heterozygous variants in the KARS1 gene. Results: With this report, we aim to contribute to the expanding of both the clinical phenotype and the allelic spectrum of lysyl-tRNA synthetase-related disorders. Our study also includes a review of previously described KARS1 cases presenting with movement disorders. Conclusions: Our findings further highlight the importance of assessing systemic involvement and performing brain and spinal neuroimaging, as well as implementing genetic screening, in infants presenting with global developmental delay, sensory deficits, and movement disorders—features that may suggest a mitochondrial disorder such as those involving ARS mutations. Full article

The family Anaplasmataceae comprises etiological agents of infectious diseases of significant importance. This study aimed to achieve the in vitro isolation and propagation of an Anaplasma sp. using tick-derived cell lines. The study was realized in Seropédica municipality, Rio de Janeiro, Brazil. Blood smears from a naturally infected bovine revealed cytoplasmic inclusions in blood cells. To isolate and propagate the organism, IDE8 and ISE6 tick cell lines derived from Ixodes scapularis were used. Two methods of inoculum preparation were employed: Histopaque^® density gradient and platelet-rich plasma separation. Following infection, cells were maintained in L-15B medium without antibiotics at 34 °C, and infection was monitored weekly by Giemsa-stained cytocentrifuge smears. After achieving ≥ 70% infection, bacteria were subcultured and successfully cryopreserved and resuscitated. PCR amplification and sequencing of 16S rDNA, 23S rDNA, rpoB, and groEL genes were performed for molecular characterization. Phylogenetic analyses revealed that the isolated strain clustered within the A. platys-like clade. This study reports the successful in vitro isolation, propagation, and cryopreservation of the ‘A. platys-like strain Natal’ bacterium in tick cell lines and provides molecular evidence supporting its phylogenetic classification. These findings contribute to the understanding of genetic variability and host–cell interactions of Anaplasma spp., laying the groundwork for future research. Full article

The assessment of a ligand’s activity is typically established by measuring its binding affinity in a biochemical assay, often expressed as K_a or K_d values. Further validation of its biological activity is achieved through cellular assays. There is frequently an inconsistency between the activity values obtained from those assays, which could delay research progress as well as drug development. Factors such as the permeability, solubility, specificity, and stability of active compounds are usually held responsible for this discrepancy. Even when these values are known, inconsistencies in activity measurements remain challenging to explain. This is not surprising since intracellular physicochemical conditions are undoubtedly different from the simplified conditions used in most in vitro biochemical assays. It is therefore reasonable to assume that these differences would be minimized if biochemical measurements were performed under conditions that more accurately mimic the intracellular environment. These physicochemical conditions can alter the K_d values. While the cellular environment has been extensively studied for decades, more recent efforts have focused on obtaining equilibrium and kinetic data directly from in-cell environments. Clarifying molecular crowding, salt composition, and lipophilic parameters inside the cell and thus their effect on molecular equilibrium is a crucial step toward replicating the intracellular environment. Full article

Coxiella burnetii, the causative agent of Q fever, is a highly infectious pathogen capable of invading diverse cell types, from alveolar macrophages to trophoblasts. Within host cells, it establishes a replicative niche named Coxiella-containing vacuole (CCV). This is driven by effector proteins secreted by the bacterium into the host cell cytoplasm via a Type 4b Secretion System (T4SS). Advances in axenic culture and mutagenesis allowed the characterization of Coxiella effector proteins, revealing their host targets and strategies of cellular subversion. This review highlights recent insights into Coxiella effector proteins and their manipulation of host processes, from vesicular trafficking to innate immunity. Full article

Chalcones are flavonoid compounds containing an α,β-unsaturated ketone core that are often found in plants and have diverse biological activities including antiviral activity. For example, chalcone 8o was previously shown to have antiviral activity against human cytomegalovirus (HCMV) and human immunodeficiency virus (HIV); two viruses that use a nuclear phase to complete their growth cycle. Here, we synthesized ten new derivatives of 8o and tested them for antiviral activity against four RNA viruses that replicate exclusively in the cytoplasm, including prototype members of the paramyxovirus, flavivirus, bunyavirus, and coronavirus families. For example, chalcones 8o and 8p showed potent inhibition of PIV5 replication with minimal cytotoxicity in human fibroblast cultures. Time-of-addition studies showed that these chalcones inhibit an early stage of viral replication and prevent viral spread through cell cultures. Most importantly, our top performing chalcones showed potent in vitro antiviral activity against Zika virus, La Crosse Virus, and the coronavirus OC43. These studies offer mechanistic insight into chalcone-mediated inhibition of viral replication, demonstrate the influence of functional group changes of chalcone scaffolds on their efficacy as antivirals, and support the development of chalcones as broad-spectrum antiviral compounds. Full article

Objectives: Oocyte quality is crucial for female fertility, but the underlying molecular mechanisms remain unclear. This study investigates the non-canonical role of the telomerase RNA protein (TERP), whose function in oogenesis is unknown, in safeguarding female gamete quality. Methods: We used gain-of-function (AT) and loss-of-function (D7) mutant mouse lines to assess oocyte quality via morphological and molecular analyses. Key methods included immunofluorescence of meiotic spindles, Western blotting for the autophagy marker LC3B, and qRT-PCR to quantify the perinatal ovarian reserve. Results: Both AT and D7 mutations caused severe meiotic spindle abnormalities, including aberrant morphology and increased size. The D7 mutation, in particular, led to impaired cytoplasmic maturation and reduced autophagy levels in oocytes. Furthermore, loss of TERP function resulted in an abnormally large ovarian reserve in newborn females, which correlated with decreased expression of autophagy and lysosomal markers in the newborn ovary. Conclusions: This study establishes a novel, non-canonical function for TERP as a crucial regulator of oocyte quality. TERP dysregulation compromises meiotic integrity and oocyte maturation by disrupting lysosome-dependent autophagy. Full article

Deer antler-derived medicinal materials, including antler velvet, antlers, and deer antler base, exhibit differential therapeutic efficacy across developmental stages, though their molecular mechanisms at the proteomic level remain uncharacterized. This study employed Data-Independent Acquisition (DIA) quantitative proteomics to systematically analyze protein profiles in sika deer antler velvet, antlers, and deer antler base. Comparative analysis revealed 3154 differentially expressed proteins (DEPs, 95% upregulated) between antler velvet and antlers, which were significantly enriched in Ribosome Biogenesis (e.g., Polyadenylate-binding protein), oxidative phosphorylation, and neurodegenerative disease pathways. In the comparison of deer antler base versus antlers, 1024 DEPs (92% upregulated) were identified, primarily involved in proteolysis (e.g., ACTC protein), glycolysis, and complement and coagulation cascades. Between deer antler base and antler velvet, 2749 DEPs (87% downregulated) were enriched in Thioredoxin domains, cytoskeleton regulation, and RNA-binding functions. Subcellular localization demonstrated antler velvet proteins predominantly distributed in the cytoplasm (37.6%) and nucleus (19.6%), while deer antler base proteins showed marked enrichment in extracellular regions (19.7%) and cytoskeletal components. As the first comprehensive proteomic characterization of these materials, this study identifies ribosomal proteins and complement pathway-related proteins as key biomarkers, thus establishing a scientific foundation for precise authentication, quality control, and efficacy–mechanism interpretation of deer antler-derived medicines. It further highlights antler velvet’s neuroprotective potential and deer antler base’s immunomodulatory applications. Full article

Pyruvate kinase (PK) is a key enzyme in glycolysis that regulates sugar metabolism and energy production, thereby influencing fruit quality. The ‘Feizixiao’ litchi, widely cultivated in Hainan Province, faces sugar reduction during fruit ripening. This study evaluated the effects of the foliar application of calcium and magnesium (Ca+Mg) during the fruit expansion stage to alleviate this problem. Ca+Mg foliar application significantly enhanced soluble sugar content, promoted peel coloration, and reduced respiration and PK activity. Genome-wide analysis identified 19 PK genes (LcPKs) exhibiting diverse exon-intron structures and conserved motifs. Phylogenetic analysis revealed both conserved and species-specific features, while subcellular localization predicted that most LcPK proteins are likely to be localized in the cytoplasm. Synteny analysis showed closer evolutionary relationships with species in the same genus than with Arabidopsis. Cis-regulatory element analysis implicated LcPKs in light response, hormone signaling, growth, and stress adaptation. Hormonal assays at 63 and 70 DAA after treatment revealed increased abscisic acid (ABA) and ethylene levels under Ca+Mg application. These hormonal changes correlated with the downregulation of LcPK3, LcPK4, LcPK5, LcPK8, and LcPK15, as confirmed by qRT-PCR, indicating negative regulation by ABA and ethylene. This regulatory mechanism likely contributes to overcoming sugar receding in litchi pulp. These findings offer insights into the regulation of sugar metabolism and strategies for enhancing fruit quality through the management of genes and nutrients. Full article

The TREX-2 complex is conserved from yeast to humans and is responsible for mRNA export from the nucleus to the cytoplasm. In yeast and humans, the TPR and Nup153 nucleoporins of the nuclear pore complex are involved in TREX-2-dependent mRNA export, but data on their involvement in this process is rather controversial. In the present work, we have studied the role of TPR and Nup153 in the TREX-2-dependent export of hsp70 mRNA in Drosophila. We have shown that Nup153 and TPR are required for the TREX-2-dependent export of hsp70 mRNA, and their knockdown leads to mRNA accumulation in the cell nucleus. We have also demonstrated that Nup153 knockdown leads to TPR relocation to the nucleoplasm. Both nucleoporins are required for TREX-2 subunits’ association with the nuclear pore. Nup153 depletion leads to the TREX-2 subunits’ relocation from the nuclear pore to the nucleoplasm. The depletion of TPR leads to PCID2 relocation to the nucleoplasm and Xmas-2 retention at the nuclear pore and does not affect ENY2 redistribution. The TREX-2 subunits form several contacts with Nup153 and TPR. Hence, both nucleoporins are involved in the interaction with TREX-2 and TREX-2-dependent export in Drosophila. Full article

Mechanical models are capable of simulating the deformation and stress distribution of oocytes under external forces, thereby providing insights into the underlying mechanisms of intracellular mechanical responses. Interactions with micromanipulation tools involve forces like compression and punction, which are effectively analyzed using principles of solid mechanics. Alternatively, fluid–structure interactions, such as shear stress at fluid junctions or pressure gradients within microchannels, are best described by a multiphase flow model. Developing the two models instead of a single comprehensive model is necessary due to the distinct nature of cell–tool interactions and cell–fluid interactions. In this study, we developed a finite element (FE) model of porcine oocytes that accounts for the viscoelastic properties of the zona pellucida (ZP) and cytoplasm for the case when the oocytes interacted with a micromanipulation tool. Atomic force microscopy (AFM) was employed to measure the Young’s modulus and creep behavior of these subcellular components that were incorporated into the FE model. When the oocyte was solely interacting with the fluids, we simulated oocyte deformation in microfluidic channels by modeling the oocyte-culture-medium system as a three-phase flow, considering the non-Newtonian behavior of the oocyte’s components. Our results show that the Young’s modulus of the ZP and cytoplasm were determined to be 7 kPa and 1.55 kPa, respectively, highlighting the differences in the mechanical properties between these subcomponents. Using the developed layered FE model, we accurately simulated oocyte deformation during their passage through a narrow-necked micropipette, with a deformation error of approximately 5.2% compared to experimental results. Using the three-phase flow model, we effectively simulated oocyte deformation in microfluidic channels under various pressures, validating the model’s efficacy through close agreement with experimental observations. This work significantly contributes to assessing oocyte quality and serves as a valuable tool for advancing cell mechanics studies. Full article

Histiocytic sarcoma (HS) is an ultra-rare hematopoietic neoplasm that frequently occurs in extranodal sites of adults. Clinically, HS demonstrates aggressive behavior and can arise de novo or in association with other hematological neoplasms. The median overall survival from the time of diagnosis is approximately six months. Histologically, HS is composed of sheets of large, round to oval cells with abundant eosinophilic cytoplasm and can be confused with a variety of benign and malignant conditions. Immunohistochemistry plays a crucial role in the diagnosis of HS, showing expression of CD163, CD68, lysozyme, and PU.1 and negative staining with follicular dendritic cell markers and myeloid cell markers. Recent studies have demonstrated a high rate of PD-L1 expression, suggesting a potential therapeutic target. Several genomic alterations have been identified in HS, including mutations involving the RAS/MAPK and PI3K/AKT/mTOR signaling pathways, CDKN2A mutations/deletions, and TP53 mutations. There is no standard protocol for the management of HS. Surgical resection with or without radiotherapy is the most common first-line treatment for unifocal/localized disease. The systemic treatment options for multifocal/disseminated disease are very limited. This review provides an overview of the current knowledge on the clinicoradiological features, histopathology, pathogenesis, and management of HS. Full article

Pyroptosis is a programmed cell death pathway that initiates and sustains inflammation to protect the host against invading pathogens or stress. Activation of caspase-1-mediated canonical pyroptosis takes place via formation of multi-protein cytoplasmic immune signaling complexes known as inflammasomes. Because we have shown previously that the canonical pyroptosis pathway plays a significant role in the pathogenesis of experimental murine cytomegalovirus (MCMV) retinal necrosis in mice with retrovirus-induced immunosuppression (MAIDS), we performed additional studies to determine whether this pathogenic involvement extends to inflammasomes as initiators of the canonical pyroptosis pathway. Initial studies demonstrated significant transcription of three different pyroptosis-associated inflammasomes, NLRP3, NLRP1b, and AIM2, within the ocular compartments of MCMV-infected eyes of MAIDS mice. Subsequent histopathologic findings revealed MCMV-infected eyes of groups of NLRP3^−/− MAIDS mice, NLRP1b^−/− MAIDS mice, or AIM2^−/− MAIDS mice each exhibited a similar atypical retinal pathology characterized by loss of photoreceptors and proliferation and/or loss of retinal pigmented epithelium but with relative sparing of the neurosensory retina, an outcome different from typical full-thickness retinal necrosis of MCMV-infected eyes of wildtype MAIDS mice. We conclude that multiple inflammasomes are individually stimulated within MCMV-infected eyes of MAIDS mice and each independently contributes to MAIDS-related MCMV full-thickness retinal necrosis pathogenesis. Full article

Breast cancer (BC) remains a leading cause of cancer-related mortality worldwide, with limited treatment options for triple-negative breast cancer (TNBC). The RNA-binding protein non-POU domain-containing octamer-binding protein (NONO) has emerged as a critical regulator of tumorigenesis, but its role in immune signaling remains unexplored. We analyzed the effect of NONO protein by modulating its expression using short hairpin RNA (shRNA) and a chemical inhibitor (R)-SKBG-1. We demonstrate that NONO depletion in MDA-MB-231 TNBC cells leads to cytoplasmic DNA accumulation, micronuclei formation, and activation of the cyclic GMP-AMP synthase—stimulator of interferon genes (cGAS/STING) pathway, resulting in enhanced modulation of the immune response. NONO-deficient cells showed increased cGAS and STING activation, Tank-binding kinase 1 (TBK1) phosphorylation, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) nuclear localization, and transcription of pro-inflammatory genes such as CC Motif Chemokine Ligand 5 (CCL5). These effects were recapitulated by pharmacological inhibition using (R)-SKBG-1, confirming NONO’s immunosuppressive function. Our findings establish NONO as a key modulator of immune activation in TNBC and suggest that its inhibition may enhance anti-tumor immunity. This work paves the way for potential combination strategies involving NONO inhibitors and immune checkpoint blockade, particularly in tumors with homologous recombination deficiencies or limited immune infiltration. Full article

The aggressiveness of oral melanoma can be related to several mutations that occur during development. Based on the knowledge of the role of transcription factors of the SOX family in other neoplastic types, it is necessary to understand their behavior in oral melanomas. In this work, the expression of SOX2, SOX3, and SOX10 and its relationship with the proliferative index and histological aspects indicative of aggressiveness in canine oral melanomas were evaluated. Thirty tumors were histologically reviewed and the expression of Melan-A, SOX2, SOX3, SOX10, and Ki67 in these tumors were determined. All tumors presented histomorphological characteristics compatible with malignant tumors and immunopositivity for Melan-A. The expression of SOX2, SOX3, and SOX10 was observed in 7/30 (23.3%), 6/30 (20%), and 23/30 (76.6%) of the cases, respectively. Among the analyzed markers, the relationship between the loss of SOX3 expression in tumors with higher proliferative rates was highlighted. An inverse correlation was also observed between the expression cytoplasmic SOX10 and nuclear SOX10, suggesting a change in the location of this protein in oral melanomas. Among the SOX family proteins studied, the SOX3 protein plays a role in the regulation of cell proliferation in oral melanomas, and it is suggested that the SOX2 and SOX10 proteins are constitutively expressed in these neoplasms, without a determining role for aggressiveness. New studies of this gene transcription pathway may assist in possible prognostic and predictive determinations of the SOX3 protein in oral canine melanoma. Full article

The liver orchestrates metabolic homeostasis through dynamic post-translational modifications. β-hydroxybutyrylation (Kbhb), a ketone body-driven modification, regulates epigenetics and metabolism in humans and mice but remains unexplored in livestock. Here, we characterize the porcine hepatic β-hydroxybutyrylome using high-resolution mass spectrometry, identifying 4982 Kbhb sites on 2122 proteins—the largest dataset to date. β-hydroxybutyrylation predominantly targets non-histone proteins (99.68%), with enrichment in fatty acid β-oxidation, TCA cycle, and oxidative phosphorylation pathways. Subcellular localization revealed cytoplasmic (38.1%), mitochondrial (18.1%), and nuclear (15.3%) dominance, reflecting BHB-CoA synthesis sites. Motif analysis identified conserved leucine, phenylalanine, and valine residues at modified lysines, suggesting enzyme-substrate specificity. β-hydroxybutyrate treatment elevated global Kbhb levels, increasing TCA intermediates (e.g., α-ketoglutarate, +9.56-fold) while reducing acetyl-CoA, indicating enhanced mitochondrial flux. Cross-species comparisons showed tissue-specific Kbhb distribution (nuclear in human cells vs. mitochondrial in mice), highlighting metabolic adaptations. This study establishes pigs as a model for Kbhb research, linking it to energy regulation and providing insights into metabolic reprogramming. Full article