Deciphering the function of the fifth class of Gα proteins: regulation of ionic homeostasis as unifying hypothesis.

Trimeric G proteins transduce signals from a superfamily of receptors and each G protein controls a wide range of cellular and systemic functions. Their highly conserved alpha subunits fall in five classes, four of which have been well investigated (Gs, Gi, G12, Gq). In contrast, the function of the fifth class, Gv is completely unknown, despite its broad occurrence and evolutionary ancient origin (older than metazoans). Here we show a dynamic presence of Gv mRNA in several organs during early development of zebrafish, including the hatching gland, the pronephros and several cartilage anlagen, employing in situ hybridisation. Next, we generated a Gv frameshift mutation in zebrafish and observed distinct phenotypes such as reduced oviposition, premature hatching and craniofacial abnormalities in bone and cartilage of larval zebrafish. These phenotypes could suggest a disturbance in ionic homeostasis as a common denominator. Indeed, we find reduced levels of calcium, magnesium and potassium in the larvae and changes in expression levels of the sodium potassium pump atp1a1a.5 and the sodium/calcium exchanger ncx1b in larvae and in the adult kidney, a major osmoregulatory organ. Additionally, expression of sodium chloride cotransporter slc12a3 and the anion exchanger slc26a4 is altered in complementary ways in adult kidney. It appears that Gv may modulate ionic homeostasis in zebrafish during development and in adults. Our results constitute the first insight into the function of the fifth class of G alpha proteins.

Effect of salinity on the physiological response and transcriptome of spotted seabass (Lateolabrax maculatus).

Salinity fluctuations significantly impact the reproduction, growth, development, as well as physiological and metabolic activities of fish. To explore the osmoregulation mechanism of aquatic organisms acclimating to salinity stress, the physiological and transcriptomic characteristics of spotted seabass (Lateolabrax maculatus) in response to varying salinity gradients were investigated. In this study, different salinity stress exerted inhibitory effects on lipase activity, while the impact on amylase activity was not statistically significant. Notably, a moderate increase in salinity (24 psu) demonstrated the potential to enhance the efficient utilization of proteins by spotted seabass. Both Na+/K+-ATPase and malondialdehyde showed a fluctuating trend of increasing and then decreasing, peaking at 72 h. Transcriptomic analysis revealed that most differentially expressed genes were involved in energy metabolism, signal transduction, the immune response, and osmoregulation. These results will provide insights into the molecular mechanisms of salinity adaptation and contribute to sustainable development of the global aquaculture industry.

(Na+, K+)- ATPase kinetics in Macrobrachium pantanalense: highlighting intra- and interspecific variation within the Macrobrachium amazonicum complex.

The Macrobrachium amazonicum complex is composed of at least the Macrobrachium amazonicum and Macrobrachium pantanalense species, with the latter described from specimens originally identified as part of an endemic M. amazonicum population in the Brazilian Pantanal region. While there may be a reproductive barrier between these two Macrobrachium species, both are phylogenetically close, with small genetic distance. However, there is currently no available biochemical information of Macrobrachium pantanalense (Na+, K+)-ATPase. Here, we report the kinetic characteristics of the gill (Na+, K+)-ATPase in two populations of M. pantanalense from Baiazinha Lagoon (Miranda, MS, Brazil) and Araguari River (Uberlândia, MG, Brazil), and compare them with Macrobrachium amazonicum populations from the Paraná-Paraguay River Basin. (Na+, K+)-ATPase activities were 67.9 ± 3.4 and 93.3 ± 4.1 nmol Pi min-1 mg-1 protein for the Baiazinha Lagoon and Araguari River populations, respectively. Two ATP hydrolyzing sites were observed for the Araguari River population while a single ATP site was observed for the Baiazinha Lagoon shrimps. Compared to the Araguari River population, a 3-fold greater apparent affinity for Mg2+ and Na+ was estimated for the Baiazinha Lagoon population, but no difference in K+ affinity and ouabain inhibition was seen. The kinetic differences observed in the gill (Na+, K+)-ATPase between the two populations of M. pantanalense, compared with those of various M. amazonicum populations, highlight interspecific divergence within the Macrobrachium genus, now examined from a biochemical perspective.

Intracranial aneurysm circulating exosome-derived LncRNA ATP1A1-AS1 promotes smooth muscle cells phenotype switching and apoptosis.

Exosomal long non-coding RNAs (LncRNAs) play a crucial role in the pathogenesis of cerebrovascular diseases. However, the expression profiles and functional significance of exosomal LncRNAs in intracranial aneurysms (IAs) remain poorly understood. Through high-throughput sequencing, we identified 1303 differentially expressed LncRNAs in the plasma exosomes of patients with IAs and healthy controls. Quantitative real-time polymerase chain reaction (qRT-PCR) verification confirmed the differential expression of LncRNAs, the majority of which aligned with the sequencing results. ATP1A1-AS1 showed the most significant upregulation in the disease group. Importantly, subsequent in vitro experiments validated that ATP1A1-AS1 overexpression induced a phenotype switching in vascular smooth muscle cells, along with promoting apoptosis and upregulating MMP-9 expression, potentially contributing to IAs formation. Furthermore, expanded-sample validation affirmed the high diagnostic value of ATP1A1-AS1. These findings suggest that ATP1A1-AS1 is a potential therapeutic target for inhibiting IAs progression and serves as a valuable clinical diagnostic marker.

[Effect and mechanism of Linggui Zhugan Decoction in regulating Sig1R on Angâ ¡-induced cardiomyocyte hypertrophy].

This study aims to explore the mechanism of Linggui Zhugan Decoction(LGZGD) in inhibiting Angiotensin Ⅱ(AngⅡ)-induced cardiomyocyte hypertrophy by regulating sigma-1 receptor(Sig1R). The model of H9c2 cardiomyocyte hypertrophy induced by AngⅡ in vitro was established by preparing LGZGD-containing serum and blank serum. H9c2 cells were divided into normal group, AngⅡ model group, 20% normal rat serum group(20% NSC), and 20% LGZGD-containing serum group. After the cells were incubated with AngⅡ(1 µmol·L~(-1)) or AngⅡ with serum for 72 h, the surface area of cardiomyocytes was detected by phalloidine staining, and the activities of Na~+-K~+-ATPase and Ca~(2+)-Mg~(2+)-ATPase were detected by micromethod. The mitochondrial Ca~(2+) levels were detected by flow cytometry, and the expression levels of atrial natriuretic peptide(ANP), brain natriuretic peptide(BNP), Sig1R, and inositol 1,4,5-triphosphate receptor type 2(IP_3R_2) were detected by Western blot. The expression of Sig1R was down-regulated by transfecting specific siRNA for investigating the efficacy of LGZGD-containing serum on cardiomyocyte surface area, Na~+-K~+-ATPase activity, Ca~(2+)-Mg~(2+)-ATPase activity, mitochondrial Ca~(2+), as well as ANP, BNP, and IP_3R_2 protein expressions. The results showed that compared with the normal group, AngⅡ could significantly increase the surface area of cardiomyocytes and the expression of ANP and BNP(P<0.01), and it could decrease the activities of Na~+-K~+-ATPase and Ca~(2+)-Mg~(2+)-ATPase, the concentration of mitochondrial Ca~(2+), and the expression of Sig1R(P<0.01). In addition, IP_3R_2 protein expression was significantly increased(P<0.01). LGZGD-containing serum could significantly decrease the surface area of cardiomyocytes and the expression of ANP and BNP(P<0.05, P<0.01), and it could increase the activities of Na~+-K~+-ATPase and Ca~(2+)-Mg~(2+)-ATPase, the concentration of mitochondrial Ca~(2+ )(P<0.01), and the expression of Sig1R(P<0.05). In addition, IP_3R_2 protein expression was significantly decreased(P<0.05). However, after Sig1R was down-regulated, the effects of LGZGD-containing serum were reversed(P<0.01). These results indicated that the LGZGD-containing serum could inhibit cardiomyocyte hypertrophy induced by AngⅡ, and its pharmacological effect was related to regulating Sig1R, promoting mitochondrial Ca~(2+ )inflow, restoring ATP synthesis, and protecting mitochondrial function.

Analysis of the sodium pump subunit ATP1A3 in glioma patients: Potential value in prognostic prediction and immunotherapy.

The ATP1A3 gene is associated with the development and progression of neurological diseases. However, the pathological function and therapeutic value of ATP1A3 in glioblastoma (GBM) remains unknown. In this study, we tried to explore the correlation between the ATP1A3 gene expression and immune features in GBM samples. We found that ATP1A3 gene expression levels showed significant negative correlation with immune checkpoints such as PD-L1, CTLA-4 and IDO1. Next, ATP1A3 gene expression levels showed significant negative correlation with the anti-cancer immune cell process, the immune score and stromal score. By grouping ATP1A3 expression levels, we found that that immunomodulator-related genes and tumor-associated immune cell effector gene expression levels were associated with lower ATP1A3 expression. In addition, immunotherapy prediction pathway activity and a majority of the anti-cancer immune cell process activity levels were also showed to be correlated with lower ATP1A3 gene expression. Further, nine prognostic factors were identified by prognostic analysis, and a GBM prognostic model (risk score) was established. We applied the model to the TCGA GBM training set sample and the GSE4412 validation set sample and found that patients in the high risk score subgroup had significantly shorter survival time, demonstrating the prognostic value and prognostic efficacy of the risk score. Furthermore, ATP1A3 overexpression has also been found to sensitize cancer cells to anti-PD-1 therapy. In conclusion, we showed that ATP1A3 is a highly promising treatment target in GBM and the risk score is an independent prognostic factor for cancer and can be used to help guide the prediction of survival time in patients with GBM.

Targeting NKAα1 to treat Parkinson's disease through inhibition of mitophagy-dependent ferroptosis.

Dysfunction of the Na+/K+-ATPase (NKA) has been documented in various neurodegenerative diseases, yet the specific role of NKAα1 in Parkinson's disease (PD) remains incompletely understood. In this investigation, we utilized NKAα1 haploinsufficiency (NKAα1+/-) mice to probe the influence of NKAα1 on dopaminergic (DA) neurodegeneration induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Our findings reveal that NKAα1+/- mice displayed a heightened loss of DA neurons and more pronounced motor dysfunction compared to the control group when exposed to MPTP. Intriguingly, this phenomenon coincided with the activation of ferroptosis and impaired mitophagy both in vivo and in vitro. To scrutinize the role and underlying mechanism of NKAα1 in PD, we employed DR-Ab, an antibody targeting the DR-region of the NKA α subunit. Our study demonstrates that the administration of DR-Ab effectively reinstated the membrane abundance of NKAα1, thereby mitigating MPTP-induced DA neuron loss and subsequent improvement in behavioral deficit. Mechanistically, DR-Ab heightened the formation of the surface NKAα1/SLC7A11 complex, inhibiting SLC7A11-dependent ferroptosis. Moreover, DR-Ab disrupted the cytosolic interaction between NKAα1 and Parkin, facilitating the translocation of Parkin to mitochondria and enhancing the process of mitophagy. In conclusion, this study establishes NKAα1 as a key regulator of ferroptosis and mitophagy, identifying its DR-region as a promising therapeutic target for PD.

The involvement of Akt, mTOR, and S6K in the in vivo effect of IGF-1 on the regulation of rat cardiac Na+/K+-ATPase.

BACKGROUND: We previously demonstrated that insulin-like growth factor-1 (IGF-1) regulates sodium/potassium adenosine triphosphatase (Na+/K+-ATPase) in vascular smooth muscle cells (VSMC) via phosphatidylinositol-3 kinase (PI3K). Taking into account that others' work show that IGF-1 activates the PI3K/protein kinase B (Akt) signaling pathway in many different cells, we here further questioned if the Akt/mammalian target of rapamycin (mTOR)/ribosomal protein p70 S6 kinase (S6K) pathway stimulates Na+/K+-ATPase, an essential protein for maintaining normal heart function. METHODS AND RESULTS: There were 14 adult male Wistar rats, half of whom received bolus injections of IGF-1 (50 µg/kg) for 24 h. We evaluated cardiac Na+/K+-ATPase expression, activity, and serum IGF-1 levels. Additionally, we examined the phosphorylated forms of the following proteins: insulin receptor substrate (IRS), phosphoinositide-dependent kinase-1 (PDK-1), Akt, mTOR, S6K, and α subunit of Na+/K+-ATPase. Additionally, the mRNA expression of the Na+/K+-ATPase α1 subunit was evaluated. Treatment with IGF-1 increases levels of serum IGF-1 and stimulates Na+/K+-ATPase activity, phosphorylation of α subunit of Na+/K+-ATPase on Ser23, and protein expression of α2 subunit. Furthermore, IGF-1 treatment increased phosphorylation of IRS-1 on Tyr1222, Akt on Ser473, PDK-1 on Ser241, mTOR on Ser2481 and Ser2448, and S6K on Thr421/Ser424. The concentration of IGF-1 in serum positively correlates with Na+/K+-ATPase activity and the phosphorylated form of mTOR (Ser2448), while Na+/K+-ATPase activity positively correlates with the phosphorylated form of IRS-1 (Tyr1222) and mTOR (Ser2448). CONCLUSION: These results indicate that the Akt/mTOR/S6K signalling pathway may be involved in the IGF-1 regulating cardiac Na+/K+-ATPase expression and activity.

Unravelling the Genetic Landscape of Hemiplegic Migraine: Exploring Innovative Strategies and Emerging Approaches.

Migraine is a severe, debilitating neurovascular disorder. Hemiplegic migraine (HM) is a rare and debilitating neurological condition with a strong genetic basis. Sequencing technologies have improved the diagnosis and our understanding of the molecular pathophysiology of HM. Linkage analysis and sequencing studies in HM families have identified pathogenic variants in ion channels and related genes, including CACNA1A, ATP1A2, and SCN1A, that cause HM. However, approximately 75% of HM patients are negative for these mutations, indicating there are other genes involved in disease causation. In this review, we explored our current understanding of the genetics of HM. The evidence presented herein summarises the current knowledge of the genetics of HM, which can be expanded further to explain the remaining heritability of this debilitating condition. Innovative bioinformatics and computational strategies to cover the entire genetic spectrum of HM are also discussed in this review.

Recurrent ATP1A1 variant Gly903Arg causes developmental delay, intellectual disability, and autism.

ATP1A1 encodes a sodium-potassium ATPase that has been linked to several neurological diseases. Using exome and genome sequencing, we identified the heterozygous ATP1A1 variant NM_000701.8: c.2707G>A;p.(Gly903Arg) in two unrelated children presenting with delayed motor and speech development and autism. While absent in controls, the variant occurred de novo in one proband and co-segregated in two affected half-siblings, with mosaicism in the healthy mother. Using a specific ouabain resistance assay in mutant transfected HEK cells, we found significantly reduced cell viability. Demonstrating loss of ATPase function, we conclude that this novel variant is pathogenic, expanding the phenotype spectrum of ATP1A1.

Fetus with multiple congenital anomaly syndrome caused by novel variant in ATP1A2.

We report a 32-year-old G3P1 at 35 weeks 3 days with a dichorionic, diamniotic twin gestation who presented for evaluation secondary to ventriculomegaly (VM) in one twin. Fetal ultrasound and MRI demonstrated microcephaly, severe VM, compression of the corpus callosum, scalp and nuchal thickening, elongated ears, bilateral talipes, right-sided congenital diaphragmatic hernia (CDH), and loss of normal cerebral architecture, indicative of a prior insult in the affected twin. The co-twin was grossly normal. The family pursued a palliative care pathway for the affected twin and was delivered at 37 weeks and 6 days. The affected twin passed away within the first hour of life due to respiratory compromise. Postmortem trio exome sequencing identified a homozygous likely pathogenic variant in ATP1A2 (c.2439+1G>A). Although this variant is novel, it is predicted to affect the donor split site in intron 17, resulting in a frameshift and complete loss-of-function of the gene. Biallelic loss of function variants in this gene have been reported in seven individuals with multiple anomalies similar to those in the affected twin. However, only one other individual with a possible CDH has been previously reported. Our case suggests that CDH be included in the phenotypic spectrum of this disorder and reports the first frameshift mutation causing this autosomal recessive multiple congenital anomaly syndrome.

ATP1A2-related epileptic encephalopathy and movement disorder: Clinical features of three novel patients.

OBJECTIVE: Variants in the ATP1A2 gene exhibit a wide clinical spectrum, ranging from familial hemiplegic migraine to childhood epilepsies and early infantile developmental epileptic encephalopathy (EIDEE) with movement disorders. This study aims to describe the epileptology of three unpublished cases and summarize epilepsy features of the other 17 published cases with ATP1A2 variants and EIDEE. METHODS: Medical records of three novel patients with pathogenic ATP1A2 variants were retrospectively reviewed. Additionally, the PUBMED, EMBASE, and Cochrane databases were searched until December 2023 for articles on EIDEE with ATP1A2 variants, without language or publication year restrictions. RESULTS: Three female patients, aged 6 months-10 years, were investigated. Epilepsy onset occurred between 5 days and 2 years, accompanied by severe developmental delay, intellectual disability, drug-resistant epilepsy, severe movement disorder, and recurrent status epilepticus. All individuals had pathogenic variants of the ATP1A2 gene (ATP1A2 c.720_721del (p.Ile240MetfsTer9), ATP1A2c.3022C > T (p.Arg1008Trp), ATP1A2 c.1096G > T (p.Gly366Cys), according to ACMG criteria. Memantine was p) rescribed to three patients, one with a reduction in ictal frequency, one with improvement in gait pattern, coordination, and attention span, and another one in alertness without significant side effects. SIGNIFICANCE: This study reinforces the association between ATP1A2 variants and a severe phenotype. All patients had de novo variants, focal motor seizures with impaired awareness as the primary type of seizure; of the 11 EEGs recorded, 10 presented a slow background rhythm, 7 multifocal interictal epileptiform discharges (IED), predominantly temporal IEDs, followed by frontal IED, as well as ten ictal recordings, which showed ictal onset from the same regions mentioned above. Treatment with antiseizure medication was generally ineffective, but memantine showed moderate improvement. Prospective studies are needed to enlarge the phenotype and assess the efficacy of NMDA receptor antagonist therapies in reducing seizure frequency and improving quality of life.

Astrocytic Na+, K+ ATPases in physiology and pathophysiology.

The Na+, K+ ATPases play a fundamental role in the homeostatic functions of astrocytes. After a brief historic prologue and discussion of the subunit composition and localization of the astrocytic Na+, K+ ATPases, the review focuses on the role of the astrocytic Na+, K+ pumps in extracellular K+ and glutamate homeostasis, intracellular Na+ and Ca2+ homeostasis and signaling, regulation of synaptic transmission and neurometabolic coupling between astrocytes and neurons. Loss-of-function mutations in the gene encoding the astrocytic α2 Na+, K+ ATPase cause a rare monogenic form of migraine with aura (familial hemiplegic migraine type 2). On the other hand, the α2 Na+, K+ ATPase is upregulated in spinal cord and brain samples from amyotrophic lateral sclerosis and Alzheimer disease patients, respectively. In the last part, the review focuses on i) the migraine relevant phenotypes shown by familial hemiplegic migraine type 2 knock-in mice with 50 % reduced expression of the astrocytic α2 Na+, K+ ATPase and the insights into the pathophysiology of migraine obtained from these genetic mouse models, and ii) the evidence that upregulation of the astrocytic α2 Na+, K+ ATPase in mouse models of amyotrophic lateral sclerosis and Alzheimer disease promotes neuroinflammation and contributes to progressive neurodegeneration.

[Clinical features of CAPOS syndrome caused by maternal ATP1A3 gene variation: a case report].

CAPOS syndrome is an autosomal dominant neurological disorder caused by mutations in the ATP1A3 gene. Initial symptoms, often fever-induced, include recurrent acute ataxic encephalopathy in childhood, featuring cerebellar ataxia, optic atrophy, areflflexia, sensorineural hearing loss, and in some cases, pes cavus. This report details a case of CAPOS syndrome resulting from a maternal ATP1A3 gene mutation. Both the child and her mother exhibited symptoms post-febrile induction,including severe sensorineural hearing loss in both ears, ataxia, areflexia, and decreased vision. Additionally, the patient's mother presented with pes cavus. Genetic testing revealed a c. 2452G>A（Glu818Lys） heterozygous mutation in theATP1A3 gene in the patient . This article aims to enhance clinicians' understanding of CAPOS syndrome, emphasizing the case's clinical characteristics, diagnostic process, treatment, and its correlation with genotypeic findings.

Improvement of Na+-K+ ATPase Activity and Gene Expression Associated with Glomerular Ultrastructural Protection in Diabetic Nephropathy by Acacia senegal: Role of Oxidative Stress Disturbances / Mejora de la actividad Na+-K+ ATPasa y la Expresión Génica Asociada con la Protección Ultraestructural Glomerular en la Nefropatía Diabética por Acacia senegal: Papel de las Alteraciones del Estrés Oxidativo

SUMMARY: This study assessed the effects of Acacia Senegal (AS) combined with insulin on Na+/K+-ATPase (NKA) activity and mRNA expression, serum glucose, renal function, and oxidative stress in a rat model of diabetic nephropathy (DN). Sixty rats were equally divided into six groups: normal control, normal+AS, diabetic (DM), DM+insulin, DM+AS, and DM+insulin+AS groups. Diabetes mellitus (type 1) was induced by a single injection of streptozotocin (65 mg/kg), and insulin and AS treatments were carried until rats were culled at the end of week 12. Serum glucose and creatinine levels, hemoglobin A1c (HbA1c) were measured. Renal homogenate levels of NKA activity and gene expression, malondialdehyde, superoxide dismutase (SOD), catalase and reduced glutathione (GSH) were evaluated as well as kidney tissue histology and ultrastructure. Diabetes caused glomerular damage and modulation of blood and tissue levels of creatinine, glucose, HbA1c, malondialdehyde, NKA activity and gene expression, SOD, catalase and GSH, which were significantly (p<0.05) treated with AS, insulin, and insulin plus AS. However, AS+insulin treatments were more effective. In conclusion, combined administration of AS with insulin to rats with DN decreased NKA activity and gene expression as well as oxidative stress, and improved glycemic state and renal structure and function.

Este estudio evaluó los efectos de Acacia senegal (AS) combinada con insulina sobre la actividad Na+/K+- ATPasa (NKA) y la expresión de ARNm, la glucosa sérica, la función renal y el estrés oxidativo en un modelo de nefropatía diabética (ND) en ratas. Sesenta ratas se dividieron equitativamente en seis grupos: control normal, normal+AS, diabética (DM), DM+insulina, DM+AS y DM+insulina+AS. La diabetes mellitus (tipo 1) se indujo mediante una única inyección de estreptozotocina (65 mg/kg), y los tratamientos con insulina y AS se llevaron a cabo hasta que las ratas fueron sacrificadas al final de la semana 12. Se midieron niveles séricos de glucosa y creatinina, hemoglobina A1c (HbA1c). Se evaluaron los niveles de homogeneizado renal de actividad NKA y expresión génica, malondialdehído, superóxido dismutasa (SOD), catalasa y glutatión reducido (GSH), así como la histología y ultraestructura del tejido renal. La diabetes causó daño glomerular y modulación de los niveles sanguíneos y tisulares de creatinina, glucosa, HbA1c, malondialdehído, actividad y expresión génica de NKA, SOD, catalasa y GSH, los cuales fueron tratados significativamente (p<0,05) con AS, insulina e insulina más AS. Sin embargo, los tratamientos con AS+insulina fueron más efectivos. En conclusión, la administración combinada de AS con insulina a ratas con DN disminuyó la actividad de NKA y la expresión genética, así como el estrés oxidativo, y mejoró el estado glucémico y la estructura y función renal.

Involvement of the Na+, K+-ATPase α1 Isoform and Endogenous Cardiac Steroids in Depression- and Manic-like Behaviors.

Bipolar disorder (BD) is a severe and common chronic mental illness characterized by recurrent mood swings between depression and mania. The biological basis of the disease is poorly understood, and its treatment is unsatisfactory. Na+, K+-ATPase is a major plasma membrane transporter and signal transducer. The catalytic α subunit of this enzyme is the binding site for cardiac steroids. Three α isoforms of the Na+, K+-ATPase are present in the brain. Previous studies have supported the involvement of the Na+, K+-ATPase and endogenous cardiac steroids (ECS) in the etiology of BD. Decreased brain ECS has been found to elicit anti-manic and anti-depressive-like behaviors in mice and rats. However, the identity of the specific α isoform involved in these behavioral effects is unknown. Here, we demonstrated that decreasing ECS through intracerebroventricular (i.c.v.) administration of anti-ouabain antibodies (anti-Ou-Ab) decreased the activity of α1+/- mice in forced swimming tests but did not change the activity in wild type (wt) mice. This treatment also affected exploratory and anxiety behaviors in α1+/- but not wt mice, as measured in open field tests. The i.c.v. administration of anti-Ou-Ab decreased brain ECS and increased brain Na+, K+-ATPase activity in wt and α1+/- mice. The serum ECS was lower in α1+/- than wt mice. In addition, a study in human participants demonstrated that serum ECS significantly decreased after treatment. These results suggest that the Na+, K+-ATPase α1 isoform is involved in depressive- and manic-like behaviors and support that the Na+, K+-ATPase/ECS system participates in the etiology of BD.

Childhood-related neural genotype-phenotype in ATP1A3 mutations: comprehensive analysis.

BACKGROUND: ATP1A3 is a gene that encodes the ATPase Na + /K + transporting subunit alpha-3 isoenzyme that is widely expressed in GABAergic neurons. It maintains metabolic balance and neurotransmitter movement. These pathways are essential for the proper functioning of the nervous system. A mutation in the ATP1A3 gene demonstrates remarkable genotype-phenotype heterogeneity. OBJECTIVES: To provide insight into patients with ATP1A3 mutation. MATERIAL AND METHODS: These cases were identified using next generation sequencing. The patients' clinical and genetic data were retrieved. Detailed revision of the literature was conducted to illustrate and compare findings. The clinical, genetical, neuroimaging, and electrophysiological data of all pediatric patients were extracted. RESULTS: The study included 14 females and 12 males in addition to two novel females cases. Their mean current age is 6.3 ± 4.24 years. There were 11.54% preterm pregnancies with 5 cases reporting pregnancy complications. Mean age of seizure onset was 1.07 ± 1.06 years. Seizure semiology included generalized tonic-clonic, staring spells, tonic-clonic, and others. Levetiracetam was the most frequently used Anti-seizure medication. The three most frequently reported classical symptoms included alternating hemiplegia of childhood (50%), cerebellar ataxia (50%), and optic atrophy (23.08%). Non-classical symptoms included dystonia (73.08%), paroxysmal dyskinesias (34.62%), and encephalopathy (26.92%). Developmental delay was reported among 84.62% in cognitive, 92.31% in sensorimotor, 80.77% in speech, and 76.92% in socioemotional. EEG and MRI were non-specific. CONCLUSION: Our study demonstrated high heterogeneity among patients with pathogenic variants in the ATP1A3 gene. Such variation is multifactorial and can be a predisposition of wide genetic and clinical variables. Many patients shared few similarities in their genetic map including repeatedly reported de novo, heterozygous, mutations in the gene. Clinically, higher females prevalence of atypical presentation was noted. These findings are validated with prior evidence and the comprehensive analysis in this study.

Cation-π Interactions Greatly Influence Ion Transportability of the Light-Driven Sodium Pump KR2: A Molecular Dynamics Study.

Krokinobacter eikastus rhodopsin 2 (KR2) is a typical light-driven sodium pump. Although wild-type KR2 exhibits high Na+ selectivity, mutagenesis performed on the residues constituting the entrance enables permeation of K+ and Cs+, while the underlying mechanism remains elusive. This study presents a comprehensive molecular dynamics investigation, including force field optimization, metadynamics, and alchemical free energy methods, to explore the N61L/G263F mutant of KR2, which exhibits transportability for K+ and Cs+. The introduced Phe263 residue can directly promote ion binding at the entrance through cation-π interactions, while the N61L mutation can enhance ion binding at Phe46 by relieving steric hindrance. These results suggest that cation-π interactions may significantly influence the ion transportability and selectivity of KR2, which can provide important insights for protein engineering and the design of artificial ion transporters.

Evaluation of the osmoregulatory capacity and three stress biomarkers in white shrimp Penaeus vannamei exposed to different temperature and salinity conditions: Na+/K+ ATPase, Heat Shock Proteins (HSP), and Crustacean Hyperglycemic Hormones (CHHs).

Salinity and temperature influence growth, survival, and reproduction of crustacean species such as Penaeus vannamei where Na +/K+-ATPase plays a key role in maintaining osmotic homeostasis in different salinity conditions. This ability is suggested to be mediated by other proteins including neuropeptides such as the crustacean hyperglycemic hormones (CHHs), and heat shock proteins (HSPs). The mRNA expression of Na+/K+-ATPase, HSP60, HSP70, CHH-A, and CHH-B1, was analyzed by qPCR in shrimp acclimated to different salinities (10, 26, and 40 PSU) and temperature conditions (20, 23, 26, 29, and 32 °C) to evaluate their uses as molecular stress biomarkers. The results showed that the hemolymph osmoregulatory capacity in shrimp changed with exposure to the different salinities. From 26 to 32 °C the Na+/K+-ATPase expression increased significantly at 10 PSU relative to shrimp acclimated at 26 PSU and at 20 °C increased at similar values independently of salinity. The highest HSP expression levels were obtained by HSP70 at 20 °C, suggesting a role in protecting proteins such as Na+/K+ -ATPase under low-temperature and salinity conditions. CHH-A was not expressed in the gill under any condition, but CHH-B1 showed the highest expression at the lowest temperatures and salinities, suggesting its participation in the Na+/K+-ATPase induction. Since Na+/K+-ATPase, HSPs, and CHHs seem to participate in maintaining the osmo-ionic balance and homeostasis in P. vannamei, their expression levels may be used as a stress biomarkers to monitor marine crustacean health status when acclimated in low salinity and temperature conditions.

Na+,K+-ATPase with Disrupted Na+ Binding Sites I and III Binds Na+ with Increased Affinity at Site II and Undergoes Na+-Activated Phosphorylation with ATP.

Na+,K+-ATPase actively extrudes three cytoplasmic Na+ ions in exchange for two extracellular K+ ions for each ATP hydrolyzed. The atomic structure with bound Na+ identifies three Na+ sites, named I, II, and III. It has been proposed that site III is the first to be occupied and site II last, when Na+ binds from the cytoplasmic side. It is usually assumed that the occupation of all three Na+ sites is obligatory for the activation of phosphoryl transfer from ATP. To obtain more insight into the individual roles of the ion-binding sites, we have analyzed a series of seven mutants with substitution of the critical ion-binding residue Ser777, which is a shared ligand between Na+ sites I and III. Surprisingly, mutants with large and bulky substituents expected to prevent or profoundly disturb Na+ access to sites I and III retain the ability to form a phosphoenzyme from ATP, even with increased apparent Na+ affinity. This indicates that Na+ binding solely at site II is sufficient to promote phosphorylation. These mutations appear to lock the membrane sector into an E1-like configuration, allowing Na+ but not K+ to bind at site II, while the cytoplasmic sector undergoes conformational changes uncoupled from the membrane sector.