Regulation Of Contraction Research Articles

Social dialogue as a contractual tool for regulating the right to work

The essence of social dialogue as a legal phenomenon has been analysed, with one of its main objectives being the implementation of contractual legal regulation of labour and social rights through reconciliation and compromises. Attention is drawn to international interest in the application of social dialogue procedures within the legal mechanism for ensuring the labour and social rights of workers. Focus is given to the form of social dialogue involving collective bargaining for the conclusion of collective agreements and contracts. The study provides a detailed analysis of certain conclusions made by the European Committee of Social Rights regarding reports from the member states of the European Social Charter (revised) on the compliance of their national legislation with the provisions of this Charter. Certain aspects of the implementation of the right to collective bargaining, enshrined in Article 6 §2 of this international treaty, are highlighted. Attention is drawn to the fact that if an industry agreement includes provisions allowing for the non-application of some of its clauses - thereby initiating a mechanism that restricts the right to work for individuals covered by this agreement or complicates the procedures for exercising the right to work - clear contractual legal conditions for applying these norms must be established. The parties to the industry agreement must define the conditions and procedures under which such a non-application clause may be invoked. The article examines the limitations of this right within the context of wage regulation. It is noted that if a collective agreement or contract has been duly concluded by the subjects of contractual regulation, any unilateral interference with its provisions can only be justified by the need to protect the rights of other workers or safeguard public interests, national security, public health, etc. The importance of improving collective contractual regulation of labour relations through mechanisms of social dialogue is emphasized, as the anticipated reform of labour legislation foresees an expansion of labour and social rights, which will need to be defined in collective agreements and contracts. The issue of the representativeness of the parties involved in social dialogue is addressed through an analysis of innovations in Ukrainian labour legislation.

Sportsman’s employment contract: problematic issues and prospects for their solution

Individual contractual regulation, which reflects the real needs of the development of relations between an employee-athlete and an employer-sports organization, plays an important role in regulating the labor activities of athletes. Thus, the employment contract concluded with an athlete contains a number of conditions that objectively and significantly individualize his work, i.e. conditions inherent only to this category of employees. Moreover, it enshrines differential conditions for each specifically defined employee­athlete. The purpose of the article is to consider the specifics of the labor contract concluded between an employee-athlete and an employer­sports organization. It was concluded that the labor relations of a professional athlete should be regulated precisely by the norms of labor law and a special law on professional sports, which regulates the entire complex of relations between the state and participants in professional sports, although today there are opinions that the work of professional athletes should be provided with the help of civil - legal regulation. It is noted that, as of today, the main national law in the field of sports - the Law «On physical culture and sports» dated 12.24.1993 concerns only the general foundations of activities in the field of physical culture and sports, at the same time, it does not even contain an acceptable definition of such a concept as «labor contract with a professional athlete». Therefore, it is proposed to supplement the specified Law with a norm to provide for the definition of an employment contract with a professional athlete. In particular, as an employment agreement between an employee­athlete and an employer-sports organization with all appendices, changes and additions, concluded in accordance with the legislation of Ukraine, on the basis of which labor relations arise regarding the preparation and participation of the athlete in competitions for a monetary reward paid by the club. At the same time, in addition to defining and enshrining at the legislative level the concept of an athlete’s employment contract, the proposal to develop a standard form of contract with athletes of various sports was supported, the development of which should be based on the main directions of the joint sports activities of the athlete and the sports organization, which directly consists in the preparation athlete to a successful performance at competitions.

Regulation of vascular smooth muscle cell contraction during early postnatal ontogenesis

Growth of the body in early postnatal ontogenesis is associated with changes in the functioning of many organ systems, including the cardiovascular system. The circulatory system of newborns is characterized by numerous structural and functional features, which at the systemic level is manifested in a significantly lower level of blood pressure. This review describes the differences in the mechanisms of regulation of vascular smooth muscle cell contraction in early postnatal ontogenesis and in adulthood, including age-related changes in the functioning of ion channels, which activity affects membrane potential level and intracellular concentration of calcium ions, as well as changes in calcium sensitivity of the contractile apparatus. The final section of the review discusses the connection between the mechanisms regulating contraction and differentiation of vascular smooth muscle cells during maturation.

The role of NAADP in maintaining spontaneous heart contractions: comparative physiological studies

The goal of the work was to study the role of the second messenger NAADP (Nicotinic Acid Adenine Dinucleotide Phosphate), which causes the release of Ca2+ ions from lysosomes and endosomes, in the regulation of heart contractions. Isolated hearts of the grape snail Helix pomatia and a chicken embryo were used as models. Using the membrane-permeable acetooxymethyl ester NAADP-AM, we showed that NAADP at nanomolar concentrations increases the frequency and amplitude of spontaneous cardiac contractions in H. pomatia. The NAADP antagonist NED19, without affecting the amplitude of contractions, dose-dependently reduces their frequency, completely blocking spontaneous contractions of the mollusk heart at a concentration of 5 μM. The V-type H+-ATPase inhibitor bafilomycin A1 suppresses the accumulation of calcium ions in lysosomes and acidic endosomes. We have shown that bafilomycin A1 causes attenuation of spontaneous contractions and cardiac arrest in H. pomatia. Serotonin increases the amplitude of contractions of the H. pomatia heart without affecting heart rate. NED19 at saturating concentrations (10 μM) reduces the frequency of contractions when the snail heart is activated by serotonin, but only partially reduces their amplitude. In experiments with the isolated chick embryo heart, we showed that NED19 reduces the frequency of spontaneous contractions without affecting the amplitude of contractions. Based on the data obtained, a hypothesis was put forward that the release of calcium ions from lysosomes and endosomes under the influence of endogenous NAADP ensures the maintenance of spontaneous contractions of the heart.

7138 Testosterone Modulation of Muscle Transcriptome Profile During Intensive Lifestyle Intervention in Older Men With Obesity and Hypogonadism

Abstract Disclosure: V. Viola: None. T. Samanta: None. M. Duremdes Nava: None. A. Celli: None. R.C. Villareal: None. N.H. Nguyen: None. G. Colleluori: None. Y. Barnouin: None. N. Napoli: None. C. Qualls: None. B.A. Kaipparettu: None. D.T. Villareal: None. Background: We reported that testosterone replacement added to lifestyle therapy can mitigate weight loss-induced reduction of muscle mass and bone mineral density (BMD) in older men with obesity and hypogonadism (Barnouin et al., J Clin Endocrinol Metab, 2021). Objective: To investigate the molecular mechanisms underlying the mitigation of muscle and BMD loss in response to testosterone replacement therapy during intensive lifestyle intervention in this at-risk population. Materials and Methods: Among the 83 older (≥ 65 y) men with obesity (BMI ≥ 30 kg/m2) and hypogonadism (early AM testosterone persistently <300 ng/dl) associated with frailty (PPT score ≤ 31) who were randomized into 26-week lifestyle therapy plus testosterone (LT+Test) or placebo (LT+Pbo), 38 underwent serial muscle biopsies for the muscle transcriptomics substudy. Results: Despite a similar 9% weight loss, lean body mass and thigh muscle volume decreased less in LT+Test than LT+Pbo (both -2% vs -4%, respectively; p=0.04). Hip BMD was preserved in LT+Test compared with LT+Pbo (0.4% vs -1.1%; p=0.03). Muscle strength increased similarly in LT+Test and LT+Pbo (23% vs 24%; p=0.95). Total testosterone increased more in LT+Test than LT+Pbo (133% vs 32%; p=0.01). Based on Next Generation Sequencing, of the 39,160 and 39,115 genes detected in LT+Test and LT+Pbo, respectively, 151 genes were differentially expressed (DEGs) in LT+Test and 114 in LT+Pbo group. Gene Ontology enrichment analyses revealed that in the LT+Test group, just four muscle-related terms (muscle organ development, muscle organ morphogenesis, regulation of skeletal muscle contraction, muscle atrophy) were downregulated, and one term (muscle system process) was upregulated while in the LT+Pbo, nine terms related to muscle (muscle system process, muscle tissue development, muscle organ development, skeletal muscle tissue development, skeletal muscle organ development, skeletal muscle cell differentiation, muscle organ morphogenesis, response to stimuli involved in regulation of muscle adaptation, muscle atrophy), and one term related to bone (bone mineralization involved in bone maturation) were downregulated. Notably, muscle system process was upregulated in the LT+Test but downregulated in the LT+Pbo. The RT-PCR analyses showed that LT+Test resulted in a higher expression of MYOD1 (p=0.02) and WNT4 (p= 0.08), key genes involved in muscle and bone metabolism, respectively, compared to LT+Pbo. Furthermore, we observed significantly higher mRNA expression of MYBPH (p=0.01), SCN3B (p=0.02), and DSC2 (p=0.01), genes involved in the muscle system process, in response to LT+Test compared to LT+Pbo. Conclusion: The addition of testosterone replacement to lifestyle therapy mitigates the weight loss-induced reduction of muscle mass and BMD via countering the weight loss-induced downregulation of genes involved in muscle and bone anabolism. Presentation: 6/2/2024

The T-Type Calcium Channel CACNA1H is Required for Smooth Muscle Cytoskeletal Organization During Tracheal Tubulogenesis.

Abnormalities of tracheal smooth muscle (SM) formation are associated with several clinical disorders including tracheal stenosis and tracheomalacia. However, the cellular and molecular mechanisms underlying tracheal SM formation remain poorly understood. Here, it is shown that the T-type calcium channel CACNA1H is a novel regulator of tracheal SM formation and contraction. Cacna1h in an ethylnitrosourea forward genetic screen for regulators of respiratory disease using the mouse as a model is identified. Cacna1h mutants exhibit tracheal stenosis, disorganized SM and compromised tracheal contraction. CACNA1H is essential to maintain actin polymerization, which is required for tracheal SM organization and tube formation. This process appears to be partially mediated through activation of the actin regulator RhoA, as pharmacological increase of RhoA activity ameliorates the Cacna1h-mutant trachea phenotypes. Analysis of human tracheal tissues indicates that a decrease in CACNA1H protein levels is associated with congenital tracheostenosis. These results provide insight into the role for the T-type calcium channel in cytoskeletal organization and SM formation during tracheal tube formation and suggest novel targets for congenital tracheostenosis intervention.

The concept of a smart contract: advantages and current situation of legal regulation in the Republic of Kazakhstan

This scientific article outlines the current provisions of the legal regulation of smart contracts, the relevance of which will grow as such contracts spread in various spheres and areas of life. Thus, the main problem of regulating relations on the use of a smart contract is the ambiguity of its legal essence, the lack of regulation in legislation, including in the Civil Code of the Republic of Kazakhstan. At the same time, some advantages of a smart contract are clearly shown by examples, which will help facilitate the process of concluding, changing, terminating and executing contracts. The main advantages of a smart contract are also discussed in detail, such as automation, transparency, security, efficiency, low intermediary costs, decentralization, flexibility and programmability. In the research, the authors touched upon the problems of fulfilling obligations in debt relations, the potential advantages and assistance of a smart contract in enforcement proceedings. The result of the exploration is a formulated definition of a smart contract and the identification of specific potential advantages of this type of non-traditional contracts. The authors summarize the results, noting the absence of a legal definition of a smart contract in the legislation of the Republic of Kazakhstan, the exclusively declarative nature of its legal regulation; the ambiguity of the range of public relations where contracts in this form are applicable, which does not allow the widespread dissemination and use of a smart contract.

THE ISSUES OF LEGAL LIABILITY IN TRANSFER RELATIONS

A transfer contract is a specific type of legal contract, which can be regulated not only by civil law but also by the corporate rules of sports federations. The regulation of transfer contracts in football is particularly relevant, as the Russian Football Union (RFU) regulates each stage of transfer relations in detail. Specifically, the RFU Regulations establish sanctions for violating the procedure of athlete transfer. These sanctions can be applied to both sports clubs and athletes. At the same time, the legal nature of these sanctions remains ambiguous, as the RFU is not a governmental body authorized to hold individuals legally liable. Nevertheless, the doctrine often highlights the concept of sports liability as a unique type of liability because the RFU has the authority to hold individuals liable under this type of liability. In addition to sports liability, the possibility of holding participants in transfer relations liable under civil law remains debatable. On the one hand, a transfer contract is a civil law agreement and, accordingly, the general provisions of the Civil Code of the Russian Federation on obligations should apply to it. On the other hand, questions arise about the possibility of combining civil sanctions with sports sanctions and about the possibility of considering civil liability prior to sports liability. In this article, the authors answered the above questions and structured the liability systems in transfer relations. Conclusions were made about situations in which sports or civil liability is applied, as well as about the possibility of applying both types of liability for a single violation by a sports club or a football player.

Characterization of contractual relations in digital turnover

The article is devoted to identifying the peculiarities of contractual relations in digital circulation. Digital turnover is becoming increasingly widespread, which leads to the emergence of new forms of contractual relations characterized by significant differences. The purpose of the article is to reveal the characteristics and peculiarities of contractual relations arising within the framework of digital civil turnover. The study of contractual relations in digital circulation is necessitated by the lack of sustainable legal regulation of this area which requires further improvement. The peculiarity of building relations in digital circulation is associated with its technical properties, primarily the need to gain access to digital platforms for the exercise of subjective rights by users. The author emphasizes that the exercise of subjective rights in digital circulation can be realized only through the use of complex intellectual property objects, in particular, those combining computer programs, databases, music, animation objects, photographs, etc. The author proposes to distinguish the following types of relations in the field of digital circulation: 1) regarding the creation and maintenance of digital circulation (legal regime of intellectual property rights); 2) organizational relations in the field of business administration of the digital environment (corporate, labor relations with the appropriate legal regime); 3) between the user and the administrator of the relevant digital environment (contractual regulation, with elements of the legal regime of personal data protection); 4) between users of the digital space regarding digital assets (a complex regime of legal regulation which may combine the legal regimes of. The author emphasizes that contractual relations in digital circulation are based on both civil law and rules and standards used in electronic systems. It is proved that different types of relations require a comprehensive application of different legal norms and are mediated by different agreements, such as: license agreements; agreements for the provision of digital services (cloud storage, marketplaces); sale and purchase of goods; exchange and pledge of digital assets; token agreements (regulating the use of cryptocurrencies and other tokens in digital ecosystems), etc.

Analysis of Implementation of Anti-Money Laundering Mechanisms in Blockchain-Based Smart Contracts under Indonesian Regulation

One of the most widely adopted forms of information technology application today is electronic trade through the internet network to make transactions. This transaction system was initially centralized, but with the risk of system failure and hacking, distributed systems such as blockchain were developed to improve security and efficiency. Blockchain also gave birth to derivative technologies such as smart contracts, automated blockchain-based digital agreements. Despite offering many advantages, the anonymity and decentralization of smart contracts raise concerns of misuse for illicit activities such as money laundering. Therefore, regulatory updates in Indonesia are needed to regulate the validity of smart contracts and money laundering actions through this technology. This article analyses the validity and regulation of smart contracts and efforts to implement the AML system in blockchain-based transactions in Indonesia.

The structural and functional effects of myosin regulatory light chain phosphorylation are amplified by increases in sarcomere length and [Ca2+

Precise regulation of sarcomeric contraction is essential for normal cardiac function. The heart must generate sufficient force to pump blood throughout the body, but either inadequate or excessive force can lead to dysregulation and disease. Myosin regulatory light chain (RLC) is a thick-filament protein that binds to the neck of the myosin heavy chain. Post-translational phosphorylation of RLC (RLC-P) by myosin light chain kinase is known to influence acto-myosin interactions, thereby increasing force production and Ca2+-sensitivity of contraction. Here, we investigated the role of RLC-P on cardiac structure and function as sarcomere length and [Ca2+] were altered. We found that at low, non-activating levels of Ca2+, RLC-P contributed to myosin head disorder, though there were no effects on isometric stress production and viscoelastic stiffness. With increases in sarcomere length and Ca2+-activation, the structural changes due to RLC-P become greater, which translates into greater force production, greater viscoelastic stiffness, slowed myosin detachment rates and altered nucleotide handling. Altogether, these data suggest that RLC-P may alter thick-filament structure by releasing ordered, off-state myosin. These more disordered myosin heads are available to bind actin, which could result in greater force production as Ca2+ levels increase. However, prolonged cross-bridge attachment duration due to slower ADP release could delay relaxation long enough to enable cross-bridge rebinding. Together, this work further elucidates the effects of RLC-P in regulating muscle function, thereby promoting a better understanding of thick-filament regulatory contributions to cardiac function in health and disease. KEY POINTS: Myosin regulatory light chain (RLC) is a thick-filament protein in the cardiac sarcomere that can be phosphorylated (RLC-P), and changes in RLC-P are associated with cardiac dysfunction and disease. This study assesses how RLC-P alters cardiac muscle structure and function at different sarcomere lengths and calcium concentrations. At low, non-activating levels of Ca2+, RLC-P contributed to myofilament disorder, though there were no effects on isometric stress production and viscoelastic stiffness. With increases in sarcomere length and Ca2+-activation, the structural changes due to RLC-P become greater, which translates into greater force production, greater viscoelastic stiffness, slower myosin detachment rate and altered cross-bridge nucleotide handling rates. This work elucidates the role of RLC-P in regulating muscle function and facilitates understanding of thick-filament regulatory protein contributions to cardiac function in health and disease.

Conflict regulation of international commercial contracts in Ukraine: modern approaches and prospects for development

Conflict regulation of international commercial contracts in Ukraine: modern approaches and prospects for development

Exploration and validation of ceRNA regulatory networks in colorectal cancer based on associations whole transcriptome sequencing

Colorectal cancer (CRC) is a wide-spread gastrointestinal cancer that is associated with augmented morbidity and mortality, and we do not yet have a deep understanding of its epidemiology and carcinogenicity. The transcriptome can reveal the complexity and heterogeneity of tumors and uncover new biomarkers or treatment options. In this study, we identified messenger RNAs (mRNAs), long non-coding RNAs (lncRNAs), round RNAs (circRNAs), and microRNAs (miRNAs) using whole-transcriptome sequencing and generated competing endogenous RNA (ceRNA) modulatory axes. We conducted whole transcriptome sequencing on 10 CRC and para-cancer (CRCP) samples and discovered 2465 differentially expressed (DE) mRNAs (DEmRNAs), 77 DE miRNAs (DEmiRNAs). 2852 DE lncRNAs (DElncRNAs) and 1477 DE circRNAs (DEcircRNAs). In addition, utilizing co-DE analysis, we generated the ceRNA axis. Subsequently, we employed the ceRNA axis to identify essential genes and corresponding associations with lncRNAs, circRNAs, and miRNAs in CRC. ceRNA regulatory network including mRNA-miRNA-lncRNA and mRNA-miRNA-circRNA. These modulatory axes potentially modulate the positive regulation of smooth muscle contraction, melanosome, plasma membrane, integral plasma membrane component and so on. Finally, the results of RNA sequencing (RNA-SEQ) were combined with the TCGA and GEO databases, and the DEGs strongly correlated with the TCGA-COAD overall survival (OS) as estimated by univariate cox and logarithmic rank analyses were cross-analyzed, and the co-upregulated DEGs were screened. Among the many DEs, KPNA2 was chosen for additional analysis. Using invitro experimentations, western blot, CCK8, EdU and other experiments were performed to verify the results. We found siRNA-based KPNA2 depletion reduces bladder cancer cells’ viability, migratory, and proliferative activities, which showed that the DEmRNA profiles were comparable to the sequencing information, confirming that the sequencing data were very reliable. These evidences highlight the ceRNA regulatory mechanisms in CRC and will aid future research into the molecular mechanisms behind colorectal cancer prevention and treatment.

Juridical Analysis of Build Operate Transfer Agreements at the Mataram Mall Building

The purpose of this research is to identify and analyze the regulation of Build Operate Transfer (BOT) agreements in positive law in Indonesia and the legal issues in the BOT agreement between the Mataram City Government and PT Pacifik Cilinaya Fantacy. The research method used is normative legal research with a legislative approach and a conceptual approach. The types of data used include secondary and primary data. Secondary data consists of literature sourced from primary, secondary, and tertiary legal materials. The regulation of Build Operate Transfer is essentially the same as general contract regulations, which are governed by the third book of the Civil Code regarding obligations. Additionally, Build Operate Transfer is also regulated by several other regulations, including: Government Regulation No. 27 of 2014, Presidential Regulation No. 13 of 2010, Minister of Finance Regulation No. 78/PMK.06/2014, and Minister of Finance Regulation No. 02/PMK.06/2008 concerning the Appraisal of State-Owned Assets. The legal issue in this Build Operate Transfer agreement is that PT Pacifik Cilinaya Fantacy failed to comply with and PT Pacifik Cilinaya Fantacy regarding the management of the APHM Cilinaya Area. PT Pacifik Cilinaya Fantacy did not fulfill its obligation to pay royalties to the Mataram City Government from 2016 to 2019.

Comparative transcriptomics of broad-spectrum and synthetic cannabidiol treated C2C12 skeletal myotubes.

Cannabidiol (CBD) is widely used in sports for recovery, pain management, and sleep improvement, yet its effects on muscle are not well understood. This study aimed to determine the transcriptional response of murine skeletal muscle myotubes to broad-spectrum CBD and synthetic CBD (sCBD). Differentiated C2C12 myotubes were treated with 10 μM CBD, sCBD, or vehicle control (DMSO) for 24 h before RNA extraction. Poly-A tail-enriched mRNA libraries were constructed and sequenced using 2 × 50 bp paired-end sequencing. CBD and sCBD treatment induced 4489 and 1979 differentially expressed genes (DEGs; p < 0.001, FDR step-up <0.05), respectively, with common upregulation of 857 genes and common downregulation of 648 genes. Common upregulated DEGs were associated with "response to unfolded protein," "cell redox homeostasis," "endoplasmic reticulum stress," "oxidative stress," and "cellular response to hypoxia." Common downregulated DEGs were linked to "sarcomere organization," "skeletal muscle tissue development," "regulation of muscle contraction," and "muscle contraction." CBD treatment induced unique DEGs compared to sCBD. The data indicate CBD may induce mild cellular stress, activating pathways associated with altered redox balance, unfolded protein response, and endoplasmic reticulum stress. We hypothesize that CBD interacts with muscle and may elicit a "mitohormetic" effect that warrants further investigation.

Abstract 62: Notch3 and the Vascular-Adipose Interactome in the Regulation of Adiponectin and Vascular Contraction

Notch3, a cell-cell interaction receptor expressed in VSMCs, is important in vascular function. Notch3 mutations cause CADASIL and aberrant Notch3 signaling is associated with vascular dysfunction/remodeling of resistance arteries, similar to the vascular phenotype in hypertension. Recent evidence suggests that Notch receptors, including Notch3, also play a role in adipose biology. Based on our previous findings that aberrant Notch3 signaling leads to vascular injury, and that perivascular adipose tissue influences vascular function we investigated a potential role for Notch3 in the vascular-adipose interactome. We characterized adipose tissue (AT) [brown AT (BAT) and white AT (WAT)] and vascular function in mice overexpressing Notch3 (N3) and in mice harboring the R169C gain of function Notch3 mutation (RC). We evaluated expression of Notch3, and its target transcription factors, BAT markers (UCP-1, OTOP-1), and production of adiponectin and IL-6. Isolated arteries from control mice were exposed to BAT conditioned medium (CM) and vascular function assessed by myography. We did not observe any changes in body weight, but BAT (N3: 115.4±7.1; RC: 115.3±8.2; WT: 154±12.1 mg, p&lt;0.05) and WAT (N3: 309.7±39; RC: 370.4±41; WT: 618.1±73 mg, p&lt;0.05) were decreased in N3 and RC mice. Expression of Notch3 target genes (Heyl, Hes5) was increased in BAT from N3 and RC mice. This was associated with increased production of adiponectin (N3: 25.1±0.4; RC: 25.8±0.6; WT: 23.6±0.4 pg/µg of tissue, p&lt;0.05) and IL-6 (N3: 45.3±5.6; RC: 51.6±5.1; WT: 33.7±2.1 pg/µg of tissue, p&lt;0.05) (by ELISA). UCP-1 expression was increased in WAT from Notch3 mice versus wildtype. Vascular contraction to U46619 was reduced by BAT CM from WT mice (EMax: 158.5±9.7% vs control 183.6±6%). This effect was enhanced with BAT CM from Notch3 (N3 and RC) mice. WAT CM from N3 and RC mice reduced vascular sensitivity to contraction (logEC50: N3=7.2±0.17M; RC=7.2±0.1M; WT: 7.7±0.1M, p&lt;0.05). In summary, at the molecular level, Notch3 regulates adipose tissue, with increased production of adiponectin in BAT and increased expression of browning markers in WAT. Functionally BAT from Notch3 mice attenuates vasoconstriction in WT mice. Our data suggest a putative role for Notch3 in the vasoprotective effects of BAT. These novel findings suggest an important role for Notch3 in the vascular:adipose interactome. Notch3 activation may influence vascular function, in part, by regulating perivascular BAT/WAT.

Calix[4]arene С-956 as a selective inhibitor of Ca2+-pump of the plasma membrane and a modulator of the contractile function in the myometrium

Background. At present, creating and testing pharmacological instruments for selective inhibition of Са2+-pump of the plasma membrane, which would become the foundation for medical preparations, for instance, for the treatment of the impaired excitability of the cardiac and smooth muscles, remains critically significant. We have demon­strated in our previous experiments that calix[4]arene С-956 is effective in inhibi­ting Са2+, Mg2+-ATPase activity of the plasma membrane of myometrium cells. The aim of this study was to investigate the regularities and mechanisms of the impact of calix[4]arene С-956 on Са2+-transporting activity of Са2+, Mg2+-ATPase of the plasma membrane (PM) and the contractile function of rat myometrium. Materials and Methods. The experiments were conducted using outbred white non-pregnant rats. Ca2+-transporting activity of myocytes PM preparations loaded with Ca2+-sensitive fluorescent probe fluo-4 AM was investigated. The registration of the contractile activity in the preparations of longitudinal smooth muscles of uterine horns with preserved endothelium was done in the isometric mode. Results. It was determined that calix[4]arene C-956 causes blocking of the transport function of the calcium pump of preparations of plasma membranes of uterine myocytes. The C-956 compound causes an increase in the amplitude of spontaneous contractions and a change in their mechanokinetic parameters during a short-term effect on multicellular preparations of rat myometrium. Calix[4]arene C-956 also significantly affects the contractions caused by high-potassium depolarization of the PM and oxytocin, increa­sing their amplitude and decreasing the rate of relaxation. Blocking the synthesis of nitric oxide significantly enhances the effects of C-956 on spontaneous and high-potassium- and oxytocin-induced contractions of the myometrium. Conclusions. The results of our research indicate that the main target of the action of calix[4]arene C-956 on myocytes is the calcium pump of the PM. With the preliminary inhibition of nitric oxide synthases followed by the use of C-956, we were able to fully demonstrate the contribution of the calcium pump of the PM to the regulation of uterine contractions.

Vascular smooth muscle BK channels limit ouabain-induced vasocontraction: Dual role of the Na/K-ATPase as a hub for Src-kinase and the Na/Ca-exchanger.

Large-conductance, calcium-activated potassium channels (BK channels) and the Na/K-ATPase are expressed universally in vascular smooth muscle. The Na/K-ATPase may act via changes in the intracellular Ca2+ concentration mediated by the Na/Ca exchanger (NCX) and via Src kinase. Both pathways are known to regulate BK channels. Whether BK channels functionally interact in vascular smooth muscle cells with the Na/K-ATPase remains to be elucidated. Thus, this study addressed the hypothesis that BK channels limit ouabain-induced vasocontraction. Rat mesenteric arteries were studied using isometric myography, FURA-2 fluorimetry and proximity ligation assay. The BK channel blocker iberiotoxin potentiated methoxamine-induced contractions. The cardiotonic steroid, ouabain (10-5 M), induced a contractile effect of IBTX at basal tension prior to methoxamine administration and enhanced the pro-contractile effect of IBTX on methoxamine-induced contractions. These facilitating effects of ouabain were prevented by the inhibition of either NCX or Src kinase. Furthermore, inhibition of NCX or Src kinase reduced the BK channel-mediated negative feedback regulation of arterial contraction. The effects of NCX and Src kinase inhibition were independent of each other. Co-localization of the Na/K-ATPase and the BK channel was evident. Our data suggest that BK channels limit ouabain-induced vasocontraction by a dual mechanism involving the NCX and Src kinase signaling. The data propose that the NCX and the Src kinase pathways, mediating the ouabain-induced activation of the BK channel, act in an independent manner.

Cooperation of aquaporin 5 and the adrenergic system in the initiation of birth in rat model

Aquaporins (AQPs) are involved in the process of implantation, regulate myometrial contractions and cervical ripening, and maintain appropriate placental functioning. The molecular mechanism of these functions is not fully understood. Our study aimed to investigate the physiological significance of AQP5 during pregnancy and to determine the cooperation between the adrenergic system and the AQP5 in uterine contraction in the late-pregnant rat uterus.After administering AQP5 siRNA intraperitoneally to Sprague-Dawley rats, the length of the gestational period was determined and the changes in uterine contractions were measured in an isolated organ bath system. Pharmacological influence on AQP5 expression and uterine contraction was investigated by treatment with terbutaline (10 mg/kg, subcutaneously) and doxazosin (5 mg/kg, orally) in vivo; and mercuric chloride (HgCl2), in vitro. Moreover, the levels of cAMP response element binding protein (CREB) were measured in the uterus by an ELISA kit.The gestational period became shorter, AQP5 expression significantly decreased and rat uterus contraction increased after AQP5 siRNA treatment compared to the control. Treatment with terbutaline significantly increased AQP5 mRNA and protein expression after 30 min and continuously reduced it until 90 min, whereas doxazosin treatment did not significantly alter AQP5 expression. Treatment with the AQP5 antagonist HgCl2 increased spontaneous uterus contraction and decreased norepinephrine-induced uterus contraction with decreasing AQP5 expression in pregnant rat uterus. Moreover, the tocolytic effect through the adrenergic system was amplified in the presence of an AQP5 antagonist, presumably via the changes in cAMP level.In conclusion, our findings elucidate the collaborative role of aquaporin 5 (AQP5) and adrenergic systems in the regulation of uterine contractions in late-pregnant rats. Our findings suggest this may be a good starting point for developing a new tocolytic therapy.

The methyltransferase SETD3 regulates mRNA alternative splicing through interacting with hnRNPK

The methyltransferase SETD3 is an enzyme essential for catalyzing histidine-73 methylation on β-Actin, thereby promoting its polymerization and regulating muscle contraction. Although increasing evidence suggests that SETD3 is involved in multiple physiological or pathological events, its biological functions remain incompletely understood. In this study, we utilize in situ proximity labeling combined with mass spectrometry analysis to detect potential interacting partners of SETD3. Unexpectedly, we find that many splicing factors are associated with SETD3. Genome-wide RNA sequencing reveals that SETD3 regulates pre-mRNA splicing events, predominantly influencing exon skipping. Biochemical and bioinformatic analyses suggest that SETD3 interacts with hnRNPK, and they collaboratively regulate exon skipping in a common subset of genes. Functionally, we demonstrate that SETD3 and hnRNPK are required for retention of exon 7 skipping in the FNIP1 gene. This promotes FNIP1-mediated nuclear translocation of the transcription factor TFEB and the subsequent induction of lysosomal and mitochondrial biogenesis. Overall, this study uncovers a novel function of SETD3 in modulating mRNA exon splicing.