Specific Role Research Articles

Ythdf2 facilitates precursor miR-378/miR-378-5p maturation to support myogenic differentiation.

Ythdf2 is known to mediate mRNA degradation in an m6A-dependent manner, and it has been shown to play a role in skeletal muscle differentiation. Recently, Ythdf2 was also found to bind to m6A-modified precursor miRNAs and regulate their maturation. However, it remains unknown whether this mechanism is related to the regulation of myogenesis by Ythdf2. Here, we observed that Ythdf2 knockdown significantly suppressed myotube formation and impacted miRNAs expression during myogenic differentiation. Through integrated analysis of miRNA and mRNA sequencing data, miR-378 and miR-378-5p were identified as important targets of Ythdf2 in myogenesis. Mechanically, Ythdf2 was found to interact with core components of the pre-miRNA processor complex, namely DICER1 and TARBP2, thereby facilitating the maturation of pre-miR-378/miR-378-5p in an m6A-dependent manner and resulting in an increase in the expression levels of mature miR-378 and miR-378-5p. Moreover, the downregulation of either miR-378 or miR-378-5p significantly inhibited myotube formation, while the forced expression of miR-378 or miR-378-5p could partially rescued Ythdf2 knockdown-induced suppression of myogenic differentiation by activating the mTOR pathway. Collectively, our results for the first time suggest that Ythdf2 regulates myogenic differentiation via mediating pre-miR-378/miR-378-5p maturation, which might provide new insights into the molecular mechanisms underlying m6A modification in the regulation of myogenesis.

ASAP1 and ARF1 regulate myogenic differentiation in rhabdomyosarcoma by modulating TAZ activity.

Despite aggressive, multimodal therapies, the prognosis of patients with refractory or recurrent rhabdomyosarcoma (RMS) has not improved in four decades. Because RMS resembles skeletal muscle precursor cells, differentiation-inducing therapy has been proposed for patients with advanced disease. In RAS-mutant PAX fusion-negative RMS (FN-FMS) preclinical models, MEK1/2 inhibition (MEKi) induces differentiation, slows tumor growth, and extends survival. However, the response is short-lived. A better understanding of the molecular mechanisms regulating FN-RMS differentiation could improve differentiation therapy. Here, we identified a role in FN-RMS differentiation for ASAP1, an ARF GTPase-activating protein (ARF GAP) with both pro-invasive and tumor suppressor functions. We found that ASAP1 knockdown inhibited differentiation in FN-RMS cells. Interestingly, knockdown of the GTPases ARF1 or ARF5, targets of ASAP1 GAP activity, also blocked differentiation of FN-RMS. We discovered that loss of ARF pathway components blocked myogenic transcription factor expression. Therefore, we examined the effects on transcriptional regulators. MEKi led to the phosphorylation and inactivation of WWTR1 (TAZ), a homolog of the pro-proliferative transcriptional co-activator YAP1 regulated by the Hippo pathway. However, loss of ASAP1 or ARF1 blocked this inactivation, which inhibits MEKi-induced differentiation. Finally, MEKi-induced differentiation was rescued by dual knockdown of ASAP1 and WWTR1. This study shows that ASAP1 and ARF1 are necessary for myogenic differentiation, providing a deeper understanding of differentiation in FN-RMS and illuminating an opportunity to advance differentiation therapy. Implications: ASAP1 and ARF1 regulate MEKi-induced differentiation of FN-RMS cells by modulating WWTR1 (TAZ) activity, supporting YAP1/TAZ inhibition as a FN-RMS differentiation therapy strategy.

RETRACTED - Cell transcription dependent on Wingless-type (Wnt)/beta-catenin in the rat estrous cycle stages

Objectives: We aimed to evaluate how T Cell Factor 7 Like 2 (TCF7L2) and Lymphoid Enhancer Factor-1 (LEF-1), which regulate cell transcription, regulate implantation in the endometrium. Methods: Female rats were determined according to the estrous cycle. The obtained uterine tissues were taken for immunofluorescence staining. Results: In estrous, LEF-1 and TCF7L2 showed localization in perimetrial-myometrial connective tissue. Of all the signaling molecules, the TCF7L2 molecule is the only one that is expressed. Non-expressed TCF7L2 in the uterine epithelium showed strong immunolocalization in the perimetrial myometrial connective tissue and endometrial basal stroma area. LEF-1 was mostly expressed in the metaestrus phase in the areas of gland epithelium. Conclusions: TCF7L2 and LEF-1 play a critical role in cell proliferation, differentiation and transcription by regulating the activation of the Wnt signaling pathway in endometrial cells. These findings help us to understand the role of TCF7L2 and LEF-1 in the provision of endometrial homeostasis and in the implantation process.

Evaluation of Guanidinoacetic Acid Supplementation on Finishing Beef Steer Growth Performance, Skeletal Muscle Cellular Response, and Carcass Characteristics.

This study elucidated the effects of dosage-dependent guanidinoacetic acid (GAA) supplementation on growth performance, muscle responses, and carcass characteristics in finishing beef steers. Thirty crossbred Red Angus beef steers (395 ± 28.09kg) were randomly assigned one of three treatments during a 146-day feedlot study: basal diet without GAA supplementation (CONTROL), 1g of GAA per 100kg of BW daily (LOWGAA), and 2g of GAA per 100kg of BW daily (HIGHGAA). Individual feed intake was monitored daily, growth performance parameters were collected every 28 days, and longissimus muscle (LM) biopsies occurred every 56 days. In biopsied LM, greater (P = 0.048) mRNA expression of IGF-1 was observed in LOWGAA steers on d 112 compared to the CONTROL group. LOWGAA steers also exhibited greater expression of myosin heavy chain (MHC) I compared to CONTROL steers (P < 0.05) and MHC IIA compared to both CONTROL and HIGHGAA treatment groups (P < 0.01) on d 112. GAA supplementation resulted in no change in carcass characteristics, serum and LM tissue metabolites, LM composition, and Warner-Bratzler shear force (WBSF) values (P > 0.05). Data collected from this study demonstrate the influence of GAA supplementation on the gene expression of MHC isoforms and their role in skeletal muscle growth, differentiation, and muscle fiber-typing.

The MCP-3/Ccr3 axis contributes to increased bone mass by affecting osteoblast and osteoclast differentiation.

Several CC subfamily chemokines have been reported to regulate bone metabolism by affecting osteoblast or osteoclast differentiation. However, the role of monocyte chemotactic protein 3 (MCP-3), a CC chemokine, in bone remodeling is not well understood. Here, we show that MCP-3 regulates bone remodeling by promoting osteoblast differentiation and inhibiting osteoclast differentiation. In a Ccr3-dependent manner, MCP-3 promoted osteoblast differentiation by stimulating p38 phosphorylation and suppressed osteoclast differentiation by upregulating interferon beta. MCP-3 increased bone morphogenetic protein 2-induced ectopic bone formation, and mice with MCP-3-overexpressing osteoblast precursor cells presented increased bone mass. Moreover, MCP-3 exhibited therapeutic effects by abrogating receptor activator of nuclear factor kappa-B ligand-induced bone loss. Therefore, MCP-3 has therapeutic potential for diseases involving bone loss due to its positive role in osteoblast differentiation and negative role in osteoclast differentiation.

Deciphering the role of NcRNAs in Pancreatic Cancer immune evasion and drug resistance: a new perspective for targeted therapy

Pancreatic cancer (PC) is a very aggressive digestive system tumor, known for its high mortality rate, low cure rate, low survival rate and poor prognosis. In particular, pancreatic ductal adenocarcinoma (PADC), which accounts for more than 90% of PC cases, has an overall 5-year survival rate of only 5%, which is an extremely critical situation. Early detection and effective treatment of PC is extremely difficult, which leads many patients to despair. In the current medical context, targeted therapy, as an important strategy for cancer treatment, is expected. However, the problems of immune escape and drug resistance in PC have become two major obstacles that are difficult to be overcome by targeted therapy. How to break through these two difficulties has become a key issue to be solved in the field of PC therapy. In recent years, non-coding RNAs (ncRNAs) have continued to heat up in the field of cancer research. NcRNAs play a pivotal role in gene regulation, cell differentiation, development, and disease processes, and their important roles in the genesis, development, and therapeutic response of PC have been gradually revealed. More importantly, ncRNAs have many advantages as therapeutic targets, such as high specificity and low side effects, making them a new favorite in the field of PC therapy. Therefore, the aim of this paper is to provide new ideas and methods for the targeted therapy of PC by reviewing the mechanism of action of four major ncRNAs (circRNAs, lncRNAs, miRNAs, siRNAs) in both immune escape and drug resistance of PC. It is expected that an effective way to overcome immune escape and drug resistance can be found through in-depth study of ncRNA, bringing a ray of hope to PC patients.

The role of Neuregulin-1 in steatotic and non-steatotic liver transplantation from donors after cardiocirculatory death

Liver grafts from donors after cardiocirculatory death (DCDs) are sometimes not considered for liver transplantation (LT). Plasma Neuregulin-1 (NRG1) is altered in cardiac abnormalities and the liver is one of the most important targets of NRG1. We study the role of NRG1 in DCD LT. Under these conditions, NRG1 was pharmacologically modulated and their pathways were characterized. NRG1 levels were increased in steatotic and non-steatotic grafts from DCDs; NRG1 was derived from adipose tissue. When NRG1 was inhibited, injury and inflammation were exacerbated. The benefits of endogenous NRG1 in DCD grafts were associated with increased hepatic accumulation of adipocyte-derived vascular endothelial growth factor-A (VEGFA). The Id1-Wnt2 signaling pathway was involved in the action mechanisms of endogenous VEGFA. Exogenous NRG1 exacerbated damage and inflammation. Here differential role of NRG1 (endogenous versus exogenous) was demonstrated and VEGFA treatment was proposed as a highly protective strategy in steatotic and non-steatotic DCD LT.

Clinical utility of anti-Müllerian hormone in female children and adolescents.

Anti-Müllerian hormone (AMH) is a dimeric glycoprotein that belongs to the transforming growth factor beta superfamily and plays essential roles in sexual differentiation and folliculogenesis. In the male embryo, AMH is produced by the Sertoli cells and induces the involution of the Müllerian ducts. In females, AMH is predominately produced by the granulosa cells of growing preantral and small antral follicles and regulates follicular maturation. Many recent studies have highlighted the significant role of this hormone in the diagnostic approach to female children and adolescents with various disorders that affect ovarian development and function. AMH is considered a valuable diagnostic tool in the management of female pediatric patients with conditions such as polycystic ovary syndrome, precocious puberty, ovarian tumors, differences in sex development, and premature ovarian insufficiency. Standardization of AMH assays, internationally approved reference values based on age and pubertal stage, and widespread availability of the test could further upgrade the clinical utility of AMH, rendering it a valuable tool in the armamentarium of physicians involved in the care of female children and adolescents, and promote future research.

Differential Localization and Functional Roles of mGluR6 Paralogs in Zebrafish Retina.

To define the location of mglur6 paralogs in the outer zebrafish retina and delineate their contribution to retina light responses across the visual spectrum. In situ hybridization and immunolocalization with custom-made antibodies were used to localize mglur6 transcripts, proteins, and additional components of the mGluR6 signaling complex. Gene editing was used to generate knockout mutants that were analyzed with white light and spectral electroretinography. Both mglur6 paralogs colocalized with known downstream pathway genes, such as trpm1a, nyctalopin, and gnaoβ. All rod photoreceptors contacted mGluR6-positive cells, while cone connectivity presented a more complex situation with no red cones and only a few UV and blue-sensitive cones connecting to mGluR6a-positive bipolar cells. All cone subtypes contacted mGluR6b-positive cells with markedly fewer red-sensitive cones. Retinas of knockout animals displayed no morphologic alterations. While ERG responses were unaffected in mglur6a knockout animals, mglur6b mutants displayed decreased responses over all spectral wavelengths. We demonstrated that mGlurR6 signalplex components are similar in the zebrafish and the mammalian retina. Despite mglur6b knockout animals having significantly impaired ERG b-wave responses, a residual b-wave persists, even in double knockouts, suggesting additional pathway components yet to be identified.

How influencers can enhance consumer responses by value co-creation

Purpose This paper aims to explore whether, how and when influencers’ value co-creation behavior in a post – influencers investing operant resources to enhance the value gained from using the product – shapes consumers’ responses toward an influencer’s recommendation. Based on value co-creation theory and consumer inference, this paper proposes that consumers infer influencers have more expertise with and more favorable attitude toward the product from value co-creation. Consequently, such behavior can foster consumer engagement and favorable attitude toward the recommended product. Design/methodology/approach The authors collected real-world data and conducted four sets of experimental studies. In the experimental studies, the presence of an influencer’s value co-creation behavior (i.e. co-creation vs. control) was manipulated to test the causal effect and mechanisms of co-creation on engagement and product attitude. Findings Results show that influencers’ value co-creation behavior positively affects consumers’ engagement and attitudes toward the product. These effects are driven by perceived influencer’s expertise with and favorability toward the product (Studies 1 and 2). Co-creating utilitarian value is more effective than co-creating hedonic value (Studies 3A and 3B). In addition, influencers with a larger number of followers benefit more from co-creation behavior than those with fewer followers (Study 4). Research limitations/implications This research adds to the literature on value co-creation by investigating how, why and when influencers’ value co-creation enhances consumer responses to the post. Our investigation concretizes value co-creation behavior in the context of influencer marketing and demonstrates its signaling effect with nuanced role of value type in shaping the effect. The findings provide a novel cue that influencers can use to enhance consumer responses to their posts. Practical implications Brands should encourage influencers to focus on value-in-use co-creation when promoting their products. While emphasizing value co-creation in influencer partnership, brands should also carefully consider the type and size of influencers they collaborate with based on the nature of their products and target audience. The research findings also provide practical implications for influencers, offering guidance on how they can optimize their content creation strategies and enhance their effectiveness in influencer marketing collaborations. Originality/value This research enriches understanding of value co-creation in the context of influencer marketing and the role of content specifics in influencers’ posts. The findings provide a novel cue that influencers can use to enhance consumer responses to their posts.

Unlocking the secrets of Cardiac development and function: the critical role of FHL2.

FHL2 (Four-and-a-half LIM domain protein 2) is a crucial factor involved in cardiac morphogenesis, the process by which the heart develops its complex structure. It is expressed in various tissues during embryonic development, including the developing heart, and has been shown to play important roles in cell proliferation, differentiation, and migration. FHL2 interacts with multiple proteins to regulate cardiac development as a coactivator or a corepressor. It is involved in cardiac specification and determination of cell fate, cardiomyocyte growth, cardiac remodeling, myofibrillogenesis, and the regulation of HERG channels. Targeting FHL2 has therapeutic implications as it could improve cardiac function, control arrhythmias, alleviate heart failure, and maintain cardiac integrity in various pathological conditions. The identification of FHL2 as a signature gene in atrial fibrillation suggests its potential as a diagnostic marker and therapeutic target for this common arrhythmia.

Workers with few hours – who secures their social rights? – The role of social dialogue and collective bargaining

This special issue looks at the contributions of social dialogue and collective bargaining to creating, maintaining or reducing the risks associated with employment contracts of few hours, such as marginal part-time work, temporary agency work and zero-hour contracts. It additionally considers changes in welfare institutions with regard to the protection of these groups of workers. In this paper, we introduce the arguments on why and how working in marginal part-time jobs involves vulnerability, and on the differential roles collective bargaining and social protection may have on these jobs, depending in particular on which status (employees, workers or self-employed) they are associated to.

Dynamic Expression of Genes Encoding Ubiquitin Conjugating Enzymes (E2s) During Neuronal Differentiation and Maturation: Implications for Neurodevelopmental Disorders and Neurodegenerative Diseases

Background: The ubiquitination process plays a crucial role in neuronal differentiation and function. Numerous studies have focused on the expression and functions of E3 ligases during these different stages, far fewer on E2 conjugating enzymes. In mice, as in humans, these E2s belong to 17 conjugating enzyme families. Objectives: We analyzed by real-time PCR the expression dynamics of all known E2 genes during an in vitro differentiation of mouse hippocampal neuronal cultures, and after, we analyzed their stimulation with N-methyl-D-aspartate (NMDA). Results: We found that 36 of the 38 E2 genes were expressed in hippocampal neurons. Many were up-regulated during neuritogenesis and/or synaptogenesis stages, such as Ube2h, Ube2b, and Aktip. Rapid and delayed responses to NMDA stimulation were associated with the increased expression of several E2 genes, such as Ube2i, the SUMO-conjugating E2 enzyme. We also observed similar expression profiles within the same E2 gene family, consistent with the presence of similar transcription factor binding sites in their respective promoter sequences. Conclusions: Our study indicates that specific expression profiles of E2 genes are correlated with changes in neuronal differentiation and activity. A better understanding of the regulation and function of E2s is needed to better understand the role played by the ubiquitination process in physiological mechanisms and pathophysiological alterations involved in neurodevelopmental or neurodegenerative diseases.

Enhancement of enteric neural stem cell neurogenesis by glial cell-derived neurotrophic factor in experimental Hirschsprung's disease.

Stem cell therapy offers a promising solution for congenital diseases like Hirschsprung's disease (HSCR). Optimizing stem cell efficacy by modifying the cells and their environment is crucial, but in vitro culture conditions need to be further improved. Glial cell-derived neurotrophic factor (GDNF) plays an important role in neuronal survival, proliferation, migration and differentiation during enteric nervous system (ENS) development. In this study, the effects of GDNF on neurites derived from an Ednrb knockout model were investigated with the aim of enhancing the neurogenic potential of enteric neural crest cells (ENCCs). Neurospheres were generated form Ednrb+/+ (control) and Ednrb-/- mice at embryonic day13.5 (E13.5) with Sox10-green fluorescent protein (Venus) transgenic expression. These neurospheres were cultured in control media and neurospheres from Ednrb-/- were cultured with either control media or media supplemented with GDNF. ENCCs differentiation was assessed using immunofluorescence staining after 18days. GDNF-treated Ednrb-/- neurospheres showed increased size and higher density of Sox10-positive ENCCs compared to untreated Ednrb-/- neurospheres. GDNF also enhanced the distribution of both TUJ1-positive neurons and S100-positive glial cells. GDNF effectively enhanced the neurogenic potential of ENCCs from HSCR animal model. This finding is crucial for the development of cell therapy in HSCR.

The dual Ras Association (RA) Domains of Drosophila Canoe have differential roles in linking cell junctions to the cytoskeleton during morphogenesis.

During development cells must change shape and move without disrupting dynamic tissue architecture. This requires robust linkage of cell-cell adherens junctions to the force-generating actomyosin cytoskeleton. Drosophila Canoe and mammalian Afadin play key roles. One central task for the field is defining mechanisms by which upstream inputs from Ras-family GTPases regulate Canoe/Afadin. They are unusual in sharing two tandem Ras-association (RA) domains, which, when deleted, virtually eliminate Canoe function. Work in vitro suggested RA1 and RA2 differ in GTPase affinity, but their individual functions in vivo remain unknown. Combining bioinformatic and biochemical approaches, we find that both RA1 and RA2 bind to active Rap1 with similar affinities, and their conserved N-terminal extensions enhance binding. We created Drosophila canoe mutants to test RA1 and RA2 function in vivo. Despite their similar affinities for Rap1, RA1 and RA2 play strikingly different roles. Deleting RA1 virtually eliminates Canoe function, while mutants lacking RA2 are viable and fertile but have defects in junctional reinforcement in embryos and during pupal eye development. These data significantly expand our understanding of regulation of adherens junction:cytoskeletal linkage.

Autophagy Regulator Rufy 4 Promotes Osteoclastic Bone Resorption by Orchestrating Cytoskeletal Organization via Its RUN Domain

Rufy4, a protein belonging to the RUN and FYVE domain-containing protein family, participates in various cellular processes such as autophagy and intracellular trafficking. However, its role in osteoclast-mediated bone resorption remains uncertain. In this study, we investigated the expression and role of the Rufy4 gene in osteoclasts using small interfering RNA (siRNA) transfection and gene overexpression systems. Our findings revealed a significant increase in Rufy4 expression during osteoclast differentiation. Silencing Rufy4 enhanced osteoclast differentiation, intracellular cathepsin K levels, and formation of axial protrusive structures but suppressed bone resorption. Conversely, overexpressing wild-type Rufy4 in osteoclasts hindered differentiation while promoting podosome formation and bone resorption. Similarly, overexpression of a Rufy4 variant lacking the RUN domain mimics the effects of Rufy4 knockdown, significantly increasing intracellular cathepsin K levels, promoting osteoclastogenesis, and elongated axial protrusions formation, yet inhibiting bone resorption. These findings indicate that Rufy4 plays a critical role in osteoclast differentiation and bone resorption by regulating the cytoskeletal organization through its RUN domain. Our study provides new insights into the molecular mechanisms governing osteoclast activity and underscores Rufy4’s potential as a novel therapeutic target for bone disorders characterized by excessive bone resorption.

Real-Time Fluorescence Visualization of the Dynamic Distribution of Zn2+ Ions during Osteoblast Differentiation.

The differentiation and maturation of osteoblasts are essential for bone formation. Zn2+ plays a crucial role in cell differentiation and is involved in osteogenic differentiation. The concentration and distribution of Zn2+ in the nucleus and cytoplasm indicate the differentiation states of osteoblasts. However, there is an absence of a real-time method for monitoring the dynamic fluctuations of endogenous Zn2+ within the nucleus. Here, a novel Zn2+ fluorescent probe (NTAD-N1) with nuclear membrane permeability was designed and developed, allowing for distribution throughout the entire cell, including the nucleus. The NTAD-N1 probe successfully showed the dynamic distribution and concentration changes of Zn2+ in the nucleus and cytoplasm of preosteoblast MC3T3-E1 during the 21-day differentiation period. The results showed that free Zn2+ increased significantly during differentiation of osteoblasts (2-21 days). Importantly, after 4 days of differentiation, osteoblasts are mainly distributed in the nucleus, which is confirmed by metallothionein expression. Subsequently, the level of free Zn2+ in the cytoplasm remained at a high level, which promoted the increase in alkaline phosphatase activity and inhibited the activity of cis-aconitase in the tricarboxylic acid cycle, resulting in the accumulation of citric acid. This series of events promotes the formation of mineralized nodules. In the process of osteoblast differentiation, the detection time of Zn2+ (≤7 days) is ahead of the late marker of alkaline phosphatase (14 days) and mineralized nodules (14-21 days). This indicates that Zn2+ can be used as a biomarker and an intervention point for early differentiation of osteoblasts.

Genome-wide identification of CAMTA genes and their expression dependence on light and calcium signaling during seedling growth and development in mung bean

BackgroundCalmodulin-binding transcription activator (CAMTA) is comprised of a group of transcription factors and plays an important role in the Ca2+ signaling pathway, mediating various molecular responses via interactions with other transcription factors and binding to the promoter region of specific genes. Mung beans (Vigna radiata) are one of the most commonly consumed commodities in Asia. To date, CAMTA proteins have not been characterized in this important crop plant.ResultsEight paralogous VrCAMTA genes were identified and found to be distributed on five of the 11 chromosomes. The proteins possessed CG-1 DNA-binding domains with bipartite NLS signals, ankyrin domains, CaM-binding IQ motifs, and CaM-binding domain (CaMBD). The 2 kb upstream regions of VrCAMTA genes contained sequence motifs of abscisic acid-responsive elements (ABRE) and ethylene-responsive elements (ERE), and binding sites for transcription factors of the bZIP and bHLH domains. Analysis of RNA-seq data from a public repository revealed ubiquitous expression of the VrCAMTA genes, as VrCAMTA1 was expressed at the highest level in seedling leaves, whereas VrCAMTA8 was expressed at the lowest level, which agreed with the RT-qPCR analysis performed on the first true leaves. On day four after leaf emergence, all VrCAMTA genes were upregulated, with VrCAMTA1 exhibiting the highest degree of upregulation. In darkness on day 4, upregulation was not observed in most VrCAMTA genes, except VrCAMTA7, for which a low degree of upregulation was found, whereas no difference was found in VrCAMTA8 expression between light and dark conditions. Treatment with calcium ionophores enhanced VrCAMTA expression under light and/or dark conditions at different times after leaf emergence, suggesting that calcium signaling is involved in the light-induced upregulation of VrCAMTA gene expression.ConclusionsThe expression dependence of nearly all VrCAMTA genes on light and calcium signaling suggests their possible differential but likely complementary roles during the early stages of mung bean growth and development.

Integration as innovation in healthcare systems.

Healthcare systems in Canada are under pressure and require change-the status quo is no longer fit for purpose, if it ever was. Innovation is often held up as a cure for what ails us, but shiny new things or novel technologies alone have not been enough. This article will explore the concepts of differentiation and integration as being important drivers in the evolution of living organisms, ecosystems, and complex human organizations. The implications of this deep pattern of systems change are essential to understanding the roles of specialization in medicine, and optionality in primary care. Specifically, overspecialization without attention to the principles of healthcare integration can lead to fragmentation of care and worse patient outcomes. Finally, this article will describe some practical examples of system integration as innovation in the form of better public health and care delivery connections, health homes, and community care coordination centres.

Nitric Oxide-Dependent Regulation of Oxygen-Related Processes in a Rat Model of Lead Neurotoxicity: Influence of the Hypoxia Resistance Factor

Background/Aims: Lead exposure is known to induce oxidative stress and neurotoxicity. Nitric oxide (NO) plays an important role in modulating oxidative stress, with L-arginine as a precursor of NO and Nω-nitro-L-arginine (L-NNA) as an inhibitor of NO synthase, an enzyme that catalyses the production of nitric oxide (NO) from L-arginine. Methods: This study investigated the differential effects of L-arginine and L-NNA on markers of oxidative stress and biochemical changes in brain tissue from rats with different levels of resistance to hypoxia exposed to lead nitrate. Rats with either low or high resistance to hypoxia were exposed to lead nitrate (oral 3.6 mg lead nitrate/kg b.w. per day for 30 days) and treated with L-arginine (600 mg/kg b.w., i.p., 30 min before and after exposure to lead nitrate) or L-NNA (35 mg/kg b.w., i.p., 30 min before and after exposure to lead nitrate). Brain tissue samples were analysed for lipid peroxidation, oxidative modification of proteins, and activity of antioxidant enzymes, including superoxide dismutase, catalase, glutathione reductase, and peroxidase, and total antioxidant status (TAS). We also examined the biomarkers of biochemical pathways involving the activity of alanine and aspartate aminotransferases, succinate dehydrogenase (SDH), and α-ketoglutarate dehydrogenase (KGDH). In addition, the trend observed was supported by assessments of the acetylcholine levels and acetylcholinesterase activity (ACh-AChE system) in brain tissue. Results: In rats with low resistance to hypoxia, the L-arginine treatment significantly reduced lipid peroxidation and oxidative protein modification but increased antioxidant enzyme activity, suggesting a protective effect against lead-induced oxidative stress. Conversely, in rats with high resistance to hypoxia, L-NNA had a protective effect, reducing lead-induced oxidative damage and decreasing lipid peroxidation, whereas L-arginine exacerbated oxidative stress and impaired antioxidant defences. These findings were supported by corresponding changes in the acetylcholine-acetylcholinesterase system, reflecting the observed patterns of lead-induced oxidative stress and neurotoxicity. The study shows that L-arginine exerts a protective effect by reducing lead-induced oxidative damage via an improvement in TAS. Our study shows that lead nitrate exposure significantly increases ala-nine and aspartate aminotransferase activity in brain tissue, with L-arginine exacerbating and L-NNA reversing this effect. The lead nitrate exposure also affected the activities of SDH and KGDH, which are important for cellular energy production and hypoxia resistance, with L-arginine altering SDH activity depending on the level of resistance and L-NNA enhancing both SDH and KGDH activities. These trends were further validated by alterations in the ACh-AChE system, highlighting the differential role of NO-dependent mechanisms in modulating lead-induced neurotoxicity based on hypoxia resistance. Conclusion: These findings suggest potential targeted therapeutic strategies based on the oxidative stress profile and highlight the potential of nitric oxide system modulators in counteracting lead-induced biochemical alterations and the dynamics of the ACh-AChE system depending on the individual physiological reactivity of organisms.