Functional Contribution Research Articles (Page 1)

Salmonella enterica relies on translocation of effector proteins through the SPI-2 type III secretion system (T3SS) for pathogenesis. More than 30 effectors contribute to manipulation of host cells through diverse mechanisms, but interdependency or redundancy between effectors complicates the discovery of effector phenotypes using single mutant strains. Here, we engineer six mutant strains to be deficient in groups of SPI-2 effectors, as defined by their reported function. Using various animal models of infection, we show that three main phenotypes define the functional contribution of the SPI-2 T3SS to infection. Multimutant strains deficient for intracellular replication, for manipulation of host cell defences, or for expression of virulence plasmid effectors all show strong attenuation in vivo, while mutants representing approximately half of the known effector complement show phenotypes similar to the wild-type parent strain. By additionally removing the SPI-1 T3SS, we find groups of effectors that contribute to SPI-2 T3SS-driven enhancement of gut inflammation. Further, we provide an example of how iterative mutation can be used to find a minimal number of effector deletions required for attenuation, and thus establish that the SPI-2 effectors SopD2 and GtgE are crucial for promotion of gut inflammation and mucosal pathology.

Alternative splicing as a novel pathogenic mechanism in chronic kidney disease.

Doxorubicin-induced cardiotoxicity (DIC) is pathologically characterized by oxidative stress and inflammatory cascades, creating an urgent need to identify therapeutic targets modulating these processes. While tumor necrosis factor alpha-induced protein 8 (TNFAIP8) has emerged as a regulator of inflammation and apoptosis, its functional role in DIC remains unexplored. This study systematically investigates TNFAIP8's cardioprotective mechanisms against DIC. A chronic DIC model was established in male C57BL/6 mice through intraperitoneal doxorubicin (DOX) administration (4mg/kg weekly for 4weeks; cumulative dose 16mg/kg). TNFAIP8 knockdown was achieved via AAV9-delivered shRNA through tail vein injection. Multimodal assessment integrating echocardiography, histopathology analysis, and molecular profiling elucidated TNFAIP8's functional and mechanistic contributions. In DOX-induced cardiomyocytes, TNFAIP8 expression was upregulated. The absence of TNFAIP8 markedly reduced DOX-triggered oxidative stress and inflammatory responses. The potential protective mechanism of TNFAIP8 deficiency against DIC involves toll-like receptor 4 (TLR4)/NF-κB signaling pathway. Importantly, administration of the TLR4 activator lipopolysaccharide (LPS) substantially reversed the cardioprotective effects observed with TNFAIP8 deletion. Our findings establish TNFAIP8 as a critical regulator of DIC pathophysiology through TLR4/NF-κB axis modulation. Pharmacological TNFAIP8 inhibition represents a viable therapeutic strategy for mitigating chemotherapy-induced cardiac dysfunction. Future investigations should prioritize developing cardiac-targeted TNFAIP8 inhibitors and validating their efficacy in large-animal DIC models.

Epigenetic upregulation of FGF2 promotes glioblastoma progression by enhancing the Warburg effect.

Esketamine relieves depressive-like behaviors in MPTP-induced Parkinson disease mice via GPR109A-dependent reduction of neuroinflammation.

MRGPRX2-Mediated Mast Cell Activation Promotes Malignant Progression of Cutaneous Squamous Cell Carcinoma via IL-17A Release.

Frailty, a geriatric syndrome marked by reduced physiological reserves, has been linked to organ dysfunction. However, the specific contribution of kidney function to frailty remains underexplored. This study aims to assess the impact of kidney function on frailty in a large population of older adults. The FRASNET cohort, including elderly, non hospitalized individuals, was evaluated for frailty, markers ofkidney, glomerular, and tubular function, and for anthropometric parameters. We included 1183 individuals in this study (59.9% females, age 65-93). Among them, 27.7% of subjects were classified asrobust, 37.6% were pre-frail, and 34.7% were frail. The prevalence of frailty increased with age (43% in individuals over 76years of age) and was associated with obesity (28.3%) and polytherapy (23.2%). Whole estimated glomerular filtration rate (eGFR) was 73.8 (IQR 62.4, 84.7) ml/min/1.73m2. The prevalence of chronic kidney disease (CKD) increased across frailty classes from 15.2% in robust to 29.0% in frail individuals (P < 0.001). Among young-old subjects (65-75years old), comorbidity was the main determinant of frailty, whereas in older subjects, when eGFR was below 53.5ml/min/1.73m2, it was associated with frailty (P < 0.002). Fractional excretion of sodium progressively increased across frailty classes, from 0.71% in robust individuals (IQR 0.46-1.03) to 0.79% in frail subjects (IQR 0.48-1.17) (P = 0.04). This study revealed a strong relationship between CKD and frailty, identifying a new eGFR threshold associated with frailty in older adults. The alterations in age- and frailty-dependent sodium handling highlight the potential role of the often-overlooked tubular function in older individuals.

While aquaculture often relies on excessive lipid intake to bolster fish growth and cut feed expenses, this practice can also result in hepatic fat accumulation, inflammatory responses, oxidative damage, and immune system malfunctions in aquatic creatures. Astaxanthin (AST), a potent antioxidant, holds promise in mitigating these detrimental effects associated with high-lipid (HL) diets. The objective of this study was to investigate the functional contributions and the fundamental molecular pathways of both synthetically produced and algae-derived Ast, focusing on their impacts on growth rates, lipid regulation, and hepatic well-being in juvenile Trachinotus ovatus maintained on diets rich in lipids. The experimental setup involved feeding T. ovatus for 8 weeks with four different diets: a control feed (CF) with normal lipid content, a HL diet, a HL diet supplemented with synthetic AST (HL + S), and a HL diet supplemented with algal-derived AST (HL + A). When compared to the HL diet, the inclusion of Ast from both sources in the feed significantly improved the growth performance and survival rate (SR) of T. ovatus. Furthermore, both forms of Ast significantly increased glutathione reductase (GR)activity and high-density lipoprotein (HDL) levels, while also decreasing the levels of lipid transport-related substances in the serum. They were also successful in mitigating hepatic lipid overload. Regarding antioxidant potential, the addition of Ast notably potentiated the Nrf2/Keap-1 signaling cascades and boosted the functionality of antioxidant enzymes. Furthermore, Ast from both synthetic and algae origins augmented the innate immune defenses of T. ovatus, leading to a decreased sensitivity to stress in the fish. To conclude, incorporating Ast from either source into the high-fat diet of T. ovatus mitigated the detrimental consequences of such a diet, including impeded growth, weakened antioxidant defenses, and weakened innate immune responses. Moreover, both sources of Ast exhibited beneficial effects on sustaining lipid metabolism homeostasis and enhancing hepatic well-being in the fish.

MADS-box genes constitute a highly conserved family of transcription factors integral to the regulation of a diverse array of plant developmental processes, encompassing floral organ specification, fruit maturation, root architecture and adaptation to abiotic stresses. These transcription factors encode proteins containing the distinctive MADS (MCM1, AGAMOUS, DEFICIENS, and SRF) domain, which mediates DNA binding and orchestrates interaction with co-regulators, thereby enabling the precise transcriptional control of developmental gene networks. Functional characterization through transgenic approaches including overexpression, knockdown, and CRISPR/Cas9-based mutagenesis-has revealed the capacity of MADS-box gene manipulation to modulate key agronomic traits, such as yield potential, as well as resilience to salinity, drought, and temperature fluctuations. In rice, targeted editing of OsMADS18 using CRISPR/Cas9 generated a substantial quantitative variation in tiller and panicle number, demonstrating the direct contribution of MADS-box gene function to biomass and yield performance. Similarly, CRISPR/Cas9-mediated disruption of the RIPENING INHIBITOR (RIN) gene in tomato (Solanum lycopersicum) underscored its central role in regulating fruit ripening, linking MADS-box gene activity to postharvest quality and development. Phylogenomic studies reveal strong conservation of MADS-box gene lineages in monocot grasses, as evidenced by clustered short internal branches, whereas eudicots, particularly Solanaceae present well-differentiated subclades, reflecting lineage-specific diversification events. Notably, network analysis highlight the high connectivity and central regulatory position of many MADS-box proteins, underlining their roles as master integrators of developmental and environmental signalling involved in both floral and vegetative transitions. A mechanistic understanding of these regulatory circuits offers translational opportunities to engineer crops with improved performance and resilience, reinforcing the pivotal role of MADS-box genes in crop improvement.

Metastasis remains the primary determinant of poor prognosis in nasopharyngeal carcinoma (NPC). While dysregulated ubiquitination drives cancer progression, the functional contributions of deubiquitinating enzymes (DUBs) to NPC dissemination are poorly defined. Here, we investigated USP2, a DUB implicated in oncogenesis, as a potential regulator of NPC migration and invasion. In our study, bioinformatics analysis of the GEO data set GSE200792 identified USP2 as a metastasis-associated gene with elevated m6A methylation and mRNA levels in metastatic NPC. Validation employed qPCR, Western blot, and immunohistochemistry in clinical samples and NPC cell lines. Functional assays included CCK-8, flow cytometry, Transwell, wound healing, and mechanistic studies such as cyclohexane chase, co-immunoprecipitation, ubiquitination assays were performed under USP2 knockdown/overexpression and NF-κB inhibition. Our results showed that USP2 was significantly upregulated in metastatic NPC tissues and cell lines. USP2 knockdown suppressed proliferation, migration, and invasion, induced apoptosis, and attenuated NF-κB activation by reducing nuclear p65 and TRAF2/MMP2 expression. Conversely, USP2 overexpression enhanced malignancy, which was reversed by NF-κB inhibition. Critically, USP2 directly bound MMP2, extended its protein half-life, and reduced K48-linked polyubiquitination. In conclusion, USP2 drives NPC migration and invasion by activating TRAF2-dependent NF-κB signaling and directly mediating K48-linked deubiquitination of MMP2, dually enhancing MMP2 expression. Targeting the USP2-MMP2 axis may offer a novel therapeutic strategy to impede NPC dissemination, addressing an unmet clinical need in advanced disease.

Biodiversity-ecosystem function (BEF) relationships have been a major topic since the 1990s, due to sustainability and extinction crises, though BEF relationships are not easily correlated with habitat, taxa, or diversity. We propose and test two predictors for BEF relationship shapes: 1) individual species abundance (indicating coexistence and competitive abilities) and functional performance, and 2) specific functions underlying a broader function. Darlingtonia californica is a carnivorous plant with modified leaves housing bacteria that contribute to insect degradation and nitrogen provision. We isolated 14 distinct bacterial strains from D. californica's leaf fluid, grew the isolates in mono- and mixed cultures, and evaluated each using insect degradation assays and protein, ammonia, nitrate, chitinase, and protease quantification assays. We ask three questions related to our two predictors of BEF shapes: 1) Can function of a bacterial community be predicted based on functions of individual species, 2) Are there correlations between bacterial species function and abundance change, 3) Does degradative function in bacterial communities correlate with nitrogen related processes in the context of this key limiting nutrient. We found that increased degradative function correlated with decreased species abundances changes, highly functioning mixed cultures could result from both highly or moderately functioning isolates, and degradative function did not rely on tested nitrogen-related functions. BEF relationships present a trade-off between degradative function and bacterial abundance changes, but not with the specific nitrogen assays. While species with strong functional contributions can also be good competitors, they may also be poor competitors or play complex roles in community assembly.

Reading comprehension is a complex cognitive skill that enables the development of a representation of the meaning of a text, promoting information acquisition and contributing to educational, social, and occupational development. Decoding plays an important role in acquiring this skill, and executive functions have been considered to contribute to it. However, studies generally do not take into account the contribution of the different executive processes (working memory, inhibition, cognitive flexibility) when considered together. This study analyzed the joint and unique contribution of executive functions to reading comprehension, controlling for their decoding level, in Spanish-speaking children aged 7 to 9 years, in the second and third grades of primary school. It was found that verbal working memory and perceptual inhibition make a significant contribution to reading comprehension, beyond their level of decoding. The results show the importance of executive functions for reading performance, especially during a stage when reading comprehension is in full development, and contribute to clarifying its role during the first years of primary school.

This study aims to investigate the contribution of lung function and respiratory muscle strength in predicting functional exercise capacity in post-myocardial infarction (MI) subjects. This cross-sectional study included 56 stable post-MI subjects. Lung function was assessed using a digital spirometer, and respiratory muscle strength was measured using an intraoral pressure meter. The 6-minute walk distance (6MWD) was conducted to assess functional exercise capacity. Correlations and multiple regression analyses were performed to evaluate predictors of 6MWD, considering demographic factors, lung function, and respiratory muscle strength. The Bland-Altman plot was used to investigate the agreement between observed and predicted 6MWDs. Significant positive correlations were found between 6MWD and forced vital capacity (FVC)%predicted (r = 0.528, P = 0.022) and maximum inspiratory pressure (MIP)%predicted (r = 0.640, P = 0.022). Age (r = -0.350, P = 0.008) and body mass index (BMI) (r= -0.561, P < 0.001) were negatively correlated with 6MWD. The best regression model included MIP%predicted (β = 0.332, P = 0.002), BMI (β = -0.264, P = 0.012), being male (β = 0.262, P = 0.003), age (β = -0.210, P = 0.020), and FVC%predicted (β = 0.219, P = 0.026) as significant unique contributors. The final multiple linear regression model was significant [F (5, 50) = 19.08, P < 0.001] and explained 65.6% of the variance (R2 = 0.656) in the 6MWD. Lung function and respiratory muscle strength significantly contribute to functional exercise capacity in post-MI. This study emphasizes the importance of comprehensive respiratory function assessments in rehabilitation strategies to improve exercise capacity in patients with post-MI.

In-depth investigation for identifying autonomous vehicle crash causations: New insights from system functions, driver behaviors and kinematics.

Background: Advanced glycation end products (AGEs) and receptors for AGEs (RAGE) have been extensively implicated in metabolic and neurodegenerative disorders due to their capacity to alter protein structure and function through non-enzymatic glycation. More recently, methylglyoxal (MG), a highly reactive glycolytic byproduct, has gained attention as a critical mediator of AGE formation and an independent contributor to cellular distress, particularly in the context of diabetes mellitus and Alzheimer’s disease. Objectives: This review synthesizes evidence from experimental and clinical studies addressing MG generation and metabolism in brain tissue, emphasizing the glyoxalase system as the primary detoxification mechanism, the functional contribution of astrocytes, and the downstream consequences of MG accumulation. In addition, we examined the interplay between MG, RAGE signaling, unfolded protein response, and regulatory mechanisms involving the hexosamine biosynthesis pathway and O-GlcNAcylation of key proteins in glucose metabolism and insulin signaling. Results and Conclusions: Brain glucose hypometabolism is a consequence of insulin resistance and results in a metabolic rearrangement that expands the glycolytic pathway and generates more MG, which, in turn, can affect insulin signaling, further compromising the molecular basis of insulin resistance and creating a vicious cycle. Astrocytes are key cells in the generation and detoxification of MG in the brain, making them a therapeutic target.

Triple-negative breast cancer (TNBC) is an aggressive and clinically challenging subtype defined by the absence of estrogen receptor, progesterone receptor, and HER2 amplification, resulting in poor prognosis and limited therapeutic options. Targeting alternative molecular pathways is urgently needed to overcome resistance and improve patient outcomes. CD147 has emerged as surface marker associated with tumor progression and immune evasion. In this study, CD147 and MHC class I-a key inhibitory ligand for natural killer cells-were analyzed in breast cancer cell lines (MCF7, MDA-MB-453, MDA-MB-231, and HCC38) using flow cytometry. The therapeutic efficacy of a humanized anti-CD147 monoclonal antibody (HuM6-1B9) was evaluated for its capacity to potentiate antibody-dependent cellular cytotoxicity (ADCC). HuM6-1B9 demonstrated the strong binding to MDA-MB-231 (KD = 4.982nM) and HCC38 (KD = 4.523nM), which are representative TNBC cell lines. In 3D spheroid models, HuM6-1B9 significantly enhanced PBMC-mediated ADCC, leading to a marked reduction in TNBC spheroid viability. Co-culture of CFSE-labeled MDA-MB-231 and HCC38 cells with primary NK cells confirmed robust ADCC, achieving 50% and 70% cytotoxicity, respectively, despite high MHC class I expression. Live-cell imaging demonstrated caspase-3/7 activation consistent with apoptosis in NK-targeted tumor cells, while CD107a degranulation and IFN-γ secretion confirmed the functional contribution of HuM6-1B9 to ADCC enhancement. Importantly, HuM6-1B9 did not promote migration or invasion in MDA-MB-231 cells, supporting its safety profile regarding metastasis. Collectively, these findings establish HuM6-1B9 as a promising immunotherapeutic candidate that overcomes immune resistance and selectively eliminates TNBC cells through ADCC without enhancing metastatic potential. By integrating mechanistic assays of NK cytotoxicity, apoptosis, and 3D tumor spheroids, this study provides clinically relevant insights underscoring the translational potential of HuM6-1B9 in TNBC immunotherapy.

Recent experimental findings challenge the traditional belief that vigilance is solely attributed to the sensorimotor system, suggesting instead that hippocampal activity, coupled with locomotor processes, enhances environmental sampling and planning. Here, we propose that hippocampal theta-nested gamma oscillations (TGOs), widely observed in experiments, play essential roles in both prediction and vigilance, in terms of recalling reward sites and avoiding unexpected dangers through synfire chains (SFCs). Despite the recognized importance of TGOs in navigation, their precise functional roles remain unclear. By building a biologically plausible spiking neuronal network model and reproducing experimental results, we leverage SFC properties-length and separation-to reveal that the positive correlation between theta frequency and motion velocity optimally balances planning for predictable events and staying alert to unexpected ones. Based on this adaptive mechanism, we further explain the distinct functional contributions of TGOs consistent with experimental findings: Theta oscillations facilitate self-location awareness, gamma oscillations enhance predictive capabilities, and their coupling ensures sufficient time windows for prediction. Our study provides insights into the functional roles of TGOs in the hippocampus, highlighting their importance in achieving both planning and vigilance during goal-directed navigation.

The aim of the research was to examine the contribution of personality traits and the functions of listening to music to the explanation of psychological well-being, and to determine whether the contribution of the functions of music to the explanation of the psychological well-being of musicians and nonmusicians differs. The research was conducted on a sample of a total of 876 participants, students of music academies and students of other study programmes from Croatia, Bosnia and Herzegovina, Serbia and Montenegro. The following instruments were used in the research: a general data questionnaire, an emotional stability scale, an intellect scale, a shortened version of the psychological well- -being scale and a shortened version of the music listening function scale. The results showed that musicians and non- -musicians differ in personality traits (musicians scored higher on both traits) and in the functions of music listening, whereby non-musicians listen to music more for stress and affect regulation, while for musicians, awe and appreciation, strong emotional experience, and identity are more important functions of music. Personality traits were a strong predictor of psychological well-being in both subsamples, but in addition to them, the functions of music also showed a significant separate contribution to psychological well-being. The results led to the conclusion that the contribution of functions of music listening to psychological well-being does not differ significantly between musicians and non-musicians.

The heparan sulfate proteoglycan syndecan-3 (SDC3) is a critical regulator of cell–matrix interactions. While other syndecan family members contribute to the progression of multiple cancers, SDC3’s functional contributions to tumor biology remain largely unexplored. This study investigates the potential role of SDC3 in the pathogenesis of breast cancer. By conducting an in-silico analysis of publicly available datasets, including TNM-plot, The Human Protein Atlas, and Kaplan–Meier Plotter, we observed that SDC3 is upregulated in breast cancer tissue. Notably, high SDC3 expression correlates with improved relapse-free survival in breast cancer patients. In vitro experiments revealed that SDC3 depletion significantly impairs cell viability, cell-cycle progression, cell migration, and 3D-spheroid-formation in MDA-MB-231 and MCF-7 breast cancer cells. Furthermore, SDC3 depletion results in upregulated gene expression of matrix metalloproteinases (MMP1, MMP9), downregulation of E-cadherin (CDH1), and altered levels of vascular endothelial growth factor A (VEGFA). Activation of proto-oncogene tyrosine-protein kinase Src was inhibited when SDC3 depletion was combined with tissue factor pathway inhibitor treatment. These findings demonstrate that breast cancer cell-derived SDC3 plays a pivotal role in tumor progression.

BackgroundEntamoeba histolytica, an enteric pathogen, causes disease by adhering to and destroying the host tissues. The interaction between the parasite and host tissue enables the rewiring of gene expression and global membrane trafficking in the parasite. A fine balance between endocytosis and exocytosis of cargoes/receptors is required to establish infection in the host. Multivesicular bodies (MVBs) act as sorting platforms, delivering cargoes/receptors to lysosomes for degradation or secreting their contents through plasma membrane fusion. Some small GTPases are known to control MVB biogenesis in various organisms. However, the functional contribution of Rab GTPases in MVB biogenesis is poorly studied in E. histolytica.ResultsHere, we identified a novel atypical protein RabD2, with an N-terminal glutamic acid-lysine rich motif and a C-terminal conserved Rab domain. Our biochemical and cell biological assays provide evidence that RabD2 self-associates, and this interaction is controlled by the N-terminal EK-rich motif and the GTPase activity mutants. RabD2 localizes on the surface of MVBs and controls their biogenesis. In line with these findings, overexpression of RabD2 upregulates ubiquitination levels, directing the decreased abundance of the heavy chain of GalNAc lectin, ultimately leading to decreased adherence of E. histolytica trophozoites to host cells.ConclusionsThus, amoebic RabD2 is a new class of Rab protein that forms high-ordered self-association variants and controls adhesion to the host cells, which impacts the pathogenesis of E. histolytica through the biogenesis of MVBs.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12915-025-02415-4.