B2 Receptor Research Articles

NOTIFICATION: Heterozygous GABAA receptor β3 subunit N110D knock‐in mice have epileptic spasms

NOTIFICATION: Heterozygous GABAA receptor β3 subunit N110D knock‐in mice have epileptic spasms

Apolipoprotein A-I priming via SR-BI and ABCA1 receptor binding upregulates mitochondrial metabolism to promote insulin secretion in INS-1E cells.

Apolipoprotein A-I (ApoA-I), the primary component of high-density lipoprotein (HDL) cholesterol primes β-cells to increase insulin secretion, however, the mechanisms involved are not fully defined. Here, we aimed to confirm ApoA-I receptors in β-cells and delineate ApoA-I-receptor pathways in β-cell insulin output. An LRC-TriCEPS experiment was performed using the INS-1E rat β-cell model and ApoA-I for unbiased identification of ApoA-I receptors. Identified targets, alongside ATP binding cassette transporter A1 (ABCA1) (included control) were silenced in the same cells, and insulin secretion (ELISA) and mitochondrial metabolism (seahorse) were assessed with/without ApoA-I priming. Human β-cell expression data was used to investigate ApoA-I receptor pathways in type 2 diabetes (T2D). Scavenger receptor B1 (SR-BI) and regulator of microtubule dynamics 1 were identified as ApoA-I targets. SR-BI or ABCA1 silencing abolished ApoA-I induced increases in insulin secretion. ApoA-I priming increased mitochondrial OXPHOS, however this was greatly attenuated with SR-BI or ABCA1 silencing. Supporting this, human β-cell expression data investigations found SR-BI and ABCA1 to be correlated with genes associated with mitochondrial pathways. In all, SR-BI and ABCA1 correlated with 73 and 3 genes differentially expressed in T2D, respectively. We confirm that SR-BI and ABCA1 are the primary β-cell ApoA-I receptors and demonstrate that ApoA-I priming enhances β-cell insulin secretion via the upregulation of mitochondrial metabolism through ApoA-I-SR-BI and ApoA-I-ABCA1 pathways. We propose that SR-BI relies on mitochondrial and exocytotic pathways, while ABCA1 depends solely on mitochondrial pathways. Our findings uncover new targets in ApoA-I β-cell mechanism for T2D therapies.

Decreased GABBA<sub>A</sub> receptor β2 subunit immunoreactivity in a rat model of autism

Decreased GABBA<sub>A</sub> receptor β2 subunit immunoreactivity in a rat model of autism

Hepatic SerpinA1 improves energy and glucose metabolism through regulation of preadipocyte proliferation and UCP1 expression.

Lipodystrophy and obesity are associated with insulin resistance and metabolic syndrome accompanied by fat tissue dysregulation. Here, we show that serine protease inhibitor A1 (SerpinA1) expression in the liver is increased during recovery from lipodystrophy caused by the adipocyte-specific loss of insulin signaling in mice. SerpinA1 induces the proliferation of white and brown preadipocytes and increases the expression of uncoupling protein 1 (UCP1) to promote mitochondrial activation in mature white and brown adipocytes. Liver-specific SerpinA1 transgenic mice exhibit increased browning of adipose tissues, leading to increased energy expenditure, reduced adiposity and improved glucose tolerance. Conversely, SerpinA1 knockout mice exhibit decreased adipocyte mitochondrial function, impaired thermogenesis, obesity, and systemic insulin resistance. SerpinA1 forms a complex with the Eph receptor B2 and regulates its downstream signaling in adipocytes. These results demonstrate that SerpinA1 is an important hepatokine that improves obesity, energy expenditure and glucose metabolism by promoting preadipocyte proliferation and activating mitochondrial UCP1 expression in adipocytes.

IMMU-04. G-AMINOBUTYRIC ACID DRIVES GLIOBLASTOMA IN FEMALES IN AN IMMUNE-DEPENDENT MANNER

Abstract Communication with a neuronal network and accumulation of myeloid-derived suppressive cells (MDSCs) support GBM growth and therapeutic resistance. GBM incidence and outcomes differ between males and females. We previously demonstrated that granulocytic (gMDSCs) drive GBM in females. However, a lack of understanding of the host factors regulating distinct MDSC subset function remains to be a major obstacle for therapeutically targeting these cells in GBM. In this study, we identified γ-aminobutyric acid (GABA) pathway as a modulator of gMDSC activity. gMDSCs from both healthy adults and glioma patients, expressed significantly higher levels of GABA receptor B1 (GABBR1) and GABA receptor B2 (GABBR2) compared to monocytic MDSCs (mMDSCs). On contrary, GABA receptor A (GABAAR) subunits were not expressed in either MDSC subtype. Given these differences, we investigated the effect of GABA on MDSC metabolism and found an increase in L-arginine metabolism specifically in female gMDSCs following GABA treatment while no significant metabolic changes were observed in any other groups. In MDSCs, L-arginine can be metabolized via nitric oxide synthase (NOS2) or Arginase-1 (Arg-1). While treatment with GABA or the GABBR agonist baclofen increased NOS2 production in specifically in female gMDSCs, Arg-1 was not affected. Mechanistically, baclofen enhanced gMDSC-mediated T cell suppression in females. In preclinical models of GBM, baclofen treatment resulted in a truncated survival only in immunocompetent female mice, which was reversed by pharmaceutical inhibition of NOS2. Clinically, female patients on GABA analogs (pregabalin, gabapentin) had significantly lower 12-month survival probabilities compared to control population. This effect was not observed in male patients. Conversely, inhibition of GABBR with CGP35348 prolonged survival in female GBM models and reprogramed the immunosuppressive tumor microenvironment. Collectively, these results highlight that GABA alters anti-tumor immune response in a sex-specific manner. These results support the future assessment of GABA pathway inhibitors as potential immunotherapy agents in GBM.

Kinin B1- and B2-Receptor Subtypes Contract Isolated Bovine Ciliary Muscle: Their Role in Ocular Lens Function and Intraocular Pressure Reduction

Background: Bradykinin is an endogenously produced nonapeptide with many physiological and pathological functions that are mediated by two pharmacologically defined receptor subtypes, B1- and B2-receptors. Current studies sought to characterize the functional bradykinin (BK) receptors present in freshly isolated bovine ciliary muscle (BCM) using an organ-bath tissue contraction system. Methods: Cumulative longitudinal isometric tension responses of BCM strips (4–5 mm) were recorded before and after the addition of test compounds to BCM strips hooked up to an isometric strain gauge transducer system. Results: BK and its analogs (7–11 concentrations) contracted BCM in a biphasic concentration-dependent manner. The first high affinity/potency phase accounted for 40–60% of the maximal contraction by each of BK (potency, EC50 = 0.9 ± 0.3 nM), Lys-BK (EC50 = 0.7 ± 0.1 nM), Met-Lys-BK (EC50 = 1 ± 0.1 nM), Hyp3-BK (EC50 = 1 ± 0.2 nM), RMP-7 (EC50 = 3.5 ± 0.5 nM), and Des-Arg9-BK (EC50 = 10 ± 0.4nM) (mean ± SEM, n = 3–8). The second lower activity phase of contraction potency values for these peptides ranged between 100 nM and 3 µM. In the presence of a selective B1-receptor antagonist (R715; 0.1–10 µM), the concentration–response curves to Des-Arg9-BK (B1-receptor agonist) were still observed, indicating activation of B2-receptors by this kinin. Likewise, when B2-receptors were completely blocked by using a B2-selective antagonist (WIN-64338; 1–10 µM), BK still induced BCM contraction, now by stimulating B1-receptors. Conclusions: This agonist/antagonist profile of BCM receptors indicated the presence of both B1- and B2-receptor subtypes, both being responsible for contracting this smooth muscle. The BCM kinin receptors may be involved in changing the shape of the ocular lens to influence accommodation, and since the ciliary muscle is attached to the trabecular meshwork through which aqueous humor drains, endogenously released kinins may regulate intraocular pressure.

New ways to repurpose salmeterol in an animal model of fibromyalgia.

Fibromyalgia (FM) is a syndrome of pervasive chronic pain accompanied by low mood, sleep disorders, and cognitive decline. The dysfunction of central pain processing systems along with neurotransmitter disturbances are possible contributing mechanisms. Genetic polymorphism of the 𝛽2 adrenergic receptors is reported in FM patients. It is reported that chronic β2 agonists administration is effective for neuropathic pain alleviation. No current information, however, exists on their potential to alleviate nociplastic pain, such as FM. Therefore, the purpose of the current study is to examine salmeterol's potential antiallodynic effects in experimentally produced FM and explore some of the possible contributing mechanisms. Thirty rats are allocated into three groups (n = 10): a normal group, a reserpine group that received reserpine (1 mg/kg; s.c.) for 3 days, and a reserpine + salmeterol group that received salmeterol (1 mg/kg; i.p.) for 21 consecutive days following last reserpine injection. Reserpine administration resulted in behavioral and biochemical changes consistent with FM, including thermal and mechanical hyperalgesia, depressive behavior, and motor incoordination. This is coupled with disturbed spinal monoamine levels, depressed cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling, disturbed mitochondrial function/dynamics, and compromised blood-nerve barrier integrity. Treatment with salmeterol conceivably reversed these effects. β2 receptor agonists such as salmeterol could be regarded as a promising strategy for the management of FM.

Highly concentrated solution of lithium chloride in organic solvents with heteroditopic receptors

Abstract The solubilization and selective extraction of lithium salts, in particular lithium chloride, in organic solvents have recently attracted attention due to the application in industry. A heteroditopic receptor 1b, which has ether oxygens and 2 urea moieties as cation and anion recognition sites, respectively, cooperatively associates with LiCl in organic solvents. The selective solid–liquid extraction of LiCl and LiBr was observed by 1H NMR in CDCl3 and MeCN-d3. It is possible to prepare highly concentrated solutions of 1b and LiCl in MeCN up to a concentration of 9.6 M, and these solutions exhibit properties similar to those of ionic liquids.

Berberine ameliorates inflammation by inhibiting MrgprB2 receptor-mediated activation of mast cell in mice

BackgroundBerberine, an isoquinoline alkaloid, is known for anti-inflammatory activities. However, the research on the anti-inflammatory mechanism of berberine is not comprehensive. Recently, studies have shown that MrgprB2 (Mas-related G-protein-coupled receptor B2) in mice and MrgprX2 (Mas-related G-protein-coupled receptor X2) in humans play vital roles in inflammation. Therefore, this study aims to investigate whether the anti-inflammatory activity of berberine is related to MrgprB2 receptor. MethodsThe anti-inflammatory activity of BH (berberine hydrochloride) was evaluated by hindpaw edema analysis, pathological analysis and RT-qPCR. Transgenic mice (MrgprB2−/− mice), HEK293T cell transfection, calcium imaging, electrophysiology, molecular docking and other methods were employed to investigate the potential relationship between the anti-inflammatory activity of BH and the MrgprB2 receptor. ResultsThe results demonstrated that BH significantly alleviated C48/80 (compound 48/80)-induced local inflammation in vivo. This was evidenced by a decrease in paw edema, reduced infiltration of inflammatory cells, inhibition of mast cell activation, and down-regulation of inflammatory factors such as CXCL13 (CXC subfamily 13) and TNF-α (tumor necrosis factor-α). It was also found that knockout of MrgprB2 receptor could block the anti-inflammatory activity of BH in mice. Furthermore, calcium imaging revealed that BH effectively inhibited the activity of MrgprB2 receptor in overexpressed HEK293T cells in vitro. Additionally, it was observed that BH also inhibited MrgprB2-mediated voltage-dependent current changes in mouse peritoneal mast cells. Molecular docking results further indicated that BH had affinity with MrgprX2 protein. ConclusionsThe anti-inflammatory mechanism of BH may be partially attributed to the inhibition of MrgprB2 receptor-mediated mast cell activation.

Kinin Receptors B1 and B2 Mediate Breast Cancer Cell Migration and Invasion by Activating the FAK-Src Axis.

Kinin receptors B1 and B2 are involved in migration and invasion in gastric, glioma, and cervical cancer cells, among others. However, the role of kinin receptors in breast cancer cells has been poorly studied. We aimed to reveal the impact of B1 and B2 receptors on migration and invasion in breast cancer cells and demonstrate their capacity to modulate in vivo tumor growth. MDA-MB-231, MCF-7, and T47D cells treated with Lys-des[Arg9]bradykinin (LDBK) or bradykinin (BK) were used to evaluate migration and invasion. Des-[Arg9]-Leu8-BK and HOE-140 were used as antagonists for the B1 and B2 receptors. MDA-MB-231 cells incubated or not with antagonists were subcutaneously inoculated in BALBc NOD/SCID mice to evaluate tumor growth. LDBK and BK treatment significantly increased migration and invasion in breast cancer cells, effects that were negated when antagonists were used. The use of antagonists in vivo inhibited tumor growth. Moreover, the migration and invasion induced by kinins in breast cancer cells were inhibited when focal adhesion kinase (FAK) and Src inhibitors were used. The novelty revealed in our work is that B1 and B2 receptors activated by LDBK and BK induce migration and invasion in breast cancer cells via a mechanism that involves the FAK-Src signaling pathway, and the antagonism of both receptors in vivo impairs breast tumor growth.

Identification of interaction partners of outer inflammatory protein A: Computational and experimental insights into how Helicobacter pylori infects host cells

Outer membrane proteins (OMPs) play a key role in facilitating the survival of Helicobacter pylori within the gastric tissue by mediating adherence. Among these proteins, Outer inflammatory protein A (OipA) is a critical factor in H. pylori colonization of the host gastric epithelial cell surface. While the role of OipA in H. pylori attachment and its association with clinical outcomes have been established, the structural mechanisms underlying OipA’s action in adherence to gastric epithelial cells remain limited. Our study employed experimental and computational approaches to investigate the interaction partners of OipA on the gastric epithelial cell surface. Initially, we conducted a proteomic analysis using a pull-down assay with recombinant OipA and gastric epithelial cell membrane proteins to identify the OipA interactome. This analysis revealed 704 unique proteins that interacted with OipA. We subsequently analyzed 16 of these OipA partners using molecular modeling tools. Among these 16 partners, we highlight three human proteins, namely Hepatocyte growth factor (HGF), Mesenchymal epithelial transition factor receptor (Met), and Adhesion G Protein-Coupled Receptor B1 (AGRB1) that could play a role in H. pylori adherence to the gastric epithelial cell surface with OipA. Collectively, these findings reveal novel host interactions mediated by OipA, suggesting their potential as therapeutic targets for combating H. pylori infection.

Aromatic Ring-Fused Amidine Based Allosteric Receptors Activated by Guest-Induced π-Conjugation Switching.

Amidine-substituted allosteric receptors 2a and 2b for benzenediols were synthesized. Receptor 2a with five-membered amidines exhibited greater allostericity than the amide-substituted receptor 1, while 2b with six-membered amidines exhibited less allostericity. NMR titration experiments revealed that a significant enthalpic factor was involved in the allostericity of these receptors. X-ray and DFT optimized structures of 2a and 2b revealed that 2a adopted a coplanar conformation with π-conjugation between the amidines and the phenylene ring of the hydrindacene framework, resulting in high allostericity due to inactivation of the initial binding.

Concerted modulation of spontaneous behavior and time-integrated whole-brain neuronal activity by serotonin receptors.

Serotonin neurons from the raphe nuclei project across the entire brain and modulate diverse physiology and behavior by acting on over a dozen receptors. Here, we took a step towards dissecting this complex process by examining the effects of agonists and antagonists of four widely expressed serotonin receptors (2A, 2C, 1A, and 1B) on spontaneous mouse behavior, which we related to time-integrated whole-brain neuronal activity as assessed by the expression of Fos, a canonical immediate-early gene product. Low-dimensional representations of behavioral and Fos map data revealed the dominant factors of variation in each domain, captured predictable differences across drug groups, and enabled predictions of behavioral changes following perturbations in Fos maps and vice versa. Our study provides a rich resource describing the effects of manipulating serotonin receptors on animal behavior and whole-brain integrated neuronal activity. It also establishes an experimental and analysis paradigm for interrogating the relationship between behavior and neuronal activity across different time scales.

The Thyroid Hormone Analog GC-1 Mitigates Acute Lung Injury by Inhibiting M1 Macrophage Polarization.

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a life-threatening condition with a high mortality rate of ≈40%. Thyroid hormones (THs) play crucial roles in maintaining homeostasis of the cellular microenvironment under stress. The previous studies confirmed that the clinical-stage TH analog GC-1 significantly alleviates pulmonary fibrosis by improving the function of mitochondria in epithelial cells. However, the effects of GC-1 on macrophages in lung injury and the related mechanisms remain unclear. This study evaluated the therapeutic effects of GC-1 in two murine models of lipopolysaccharide (LPS)- or hydrochloric acid (HCl)-induced ALI. Additionally, mouse alveolar macrophages (AMs) and human THP-1-derived macrophages are utilized to investigate the impact of GC-1 on macrophage polarization. GC-1 effectively reduces the inflammatory response and lung injury in ALI mice, as evidenced by neutrophil infiltration, cytokine levels, alveolar fluid clearance, and pulmonary pathology. Notably, GC-1 selectively inhibits M1 macrophage polarization, which may be achieved by impeding NF-κB signaling activation through the DNMT3b-PPARγ-NF-κB pathway in a TH receptor β1 (TRβ1)-dependent manner, consequently suppressing the polarization of macrophages toward the M1 phenotype and overproduction of inflammatory cytokines. Overall, these findings highlight the immunomodulatory property of GC-1 as an anti-inflammatory strategy for ALI/ARDS and inflammation-related diseases.

Hypothalamus-sympathetic-liver axis mediates the early phase of stress-induced hyperglycemia in the male mice

Rapid glucose supply is crucial for animal survival during stress response. How the timescale of stress-induced glucose release precisely controlled by hypothalamic corticotropin-releasing hormone (CRH) neurons remains unclear. Here, we show that stress-induced hyperglycemia can be divided into at least two stages in male mice: the first fast stage is mediated by hypothalamus (paraventricular to ventromedial hypothalamus)-sympathetic (raphe pallidus nucleus to intermediolateral nucleus)-liver (HSL) axis activity; the second delayed stage is mediated by adrenal activity. Blocking the activity of HSL axis impairs predatory evoked flight responses, indicating that the HSL pathway activity is necessary for stress coping. We further reveal the intracellular signal cascade for CRH signal in the hypothalamus, which is mediated by GABAA receptor β3 subunit phosphorylation at S408/409, results in prevention of GABAA receptor membrane recruitment. Thus, we uncovered the precise timescale of glucose supply during stress which is mediated by adrenal independent HSL and adrenal dependent pathway respectively.

Involvement of the Kinin B1 Receptor in Increased Permeability of Cerebral Microvessels in Rats Subjected to Autoimmune Encephalomyelitis.

Kinins are vasoactive peptides that are involved in various cellular mechanisms, including the inflammatory response. Kinins, released in vessel walls, exacerbate inflammation by modulating the production and release of pro-inflammatory factors via two types of G protein-related receptors-B1 and B2 receptors. B1 R is overexpressed during the inflammation that accompanies numerous neurological disorders, including multiple sclerosis (MS), in which loss of BBB integrity is an early pathomechanism of the disease. In this work, we apply pharmacological inhibition of the kinin B1 receptor with DALBK to investigate its effect on blood-brain barrier (BBB) permeability during the course of EAE, an animal model of MS. Functional, ultrastructural and molecular analyses were performed. The expression of selected BBB-associated proteins such as occludin and claudin-5 was assessed, as well as the astrocytic marker GFAP. We show that administration of a specific antagonist attenuates neurological symptoms in EAE rats and recovers the downregulation of TJ proteins and BBB leakage observed during the course of the disease, as well as significantly reducing the disease-specific activation of astroglia. The results show that B1 R-mediated signaling is involved in inducing molecular changes at the level of cerebral microvessels, leading to increased permeability of the BBB following neuroinflammation in EAE.

Diversification of Antibodies: From V(D)J Recombination to Somatic Exon Shuffling.

Antibodies that gain specificity by a large insert encoding for an extra domain were described for the first time in 2016. In malaria-exposed individuals, an exon deriving from the leukocyte-associated immunoglobulin-like 1 (LAIR1) gene integrated via a copy-and-paste insertion into the immunoglobulin heavy chain encoding region. A few years later, a second example was identified, namely a dual exon integration from the leukocyte immunoglobulin-like receptor B1 (LILRB1) gene that is located in close proximity to LAIR1. A dedicated high-throughput characterization of chimeric immunoglobulin heavy chain transcripts unraveled, that insertions from distant genomic regions (including mitochondrial DNA) can contribute to human antibody diversity. This review describes the modalities of insert-containing antibodies. The role of known DNA mobility aspects, such as genomic translocation, gene conversion, and DNA fragility, is discussed in the context of insert-antibody generation. Finally, the review covers why insert antibodies were omitted from the past repertoire analyses and how insert antibodies can contribute to protective immunity or an autoreactive response.

Molecular responses in the intestine of Atlantic salmon (Salmo salar) following light and diet stimulation of smoltification: Potential molecular markers for a seawater-ready smolt

The transfer to seawater (SW) represents a critical stage in the production of Atlantic salmon. The success of the transfer links with the optimal development of hypo-osmoregulatory capacities during smoltification. While various strategies are adopted in aquaculture to stimulate smoltification, considerable fish loss still occurs after transfer to sea cages. Therefore, we investigated the molecular responses in the anterior and posterior intestine of Atlantic salmon, following 1) a photoperiod treatment (24 h light (L):0 h dark (D) → 24 L:0D vs. 7 L:17D → 24 L:0D) and 2) dietary treatment (regular feed or feed enriched with a salt mix/tryptophan), combined with, or without a photoperiodic treatment in freshwater (FW), to evaluate how intestinal osmoregulatory mechanisms are modulated by these treatments, and to identify potential intestinal markers indicative of a SW-ready smolt. Using quantitative real-time PCR (qPCR), we investigated transcript levels of transporters and channels involved in ion movements through the enterocytes, tight junction components, and receptors (i.e., calcium-sensing receptor and prolactin receptor). The two intestinal regions showed different gene profiles and responsiveness towards the experimental treatments. In the anterior intestine, the exposure to short photoperiod (7 L:17D) upregulated Na+/K+ − ATPase subunit alpha 1c (nkaα1c), Na+/K+/2Cl− cotransporter 1 (nkcc1), Na+/K+/2Cl− cotransporter 2 (nkcc2), Cl−/HCO3− exchanger Slc26a6 (slc26a6), and cystic fibrosis transmembrane conductance regulator I (cftrI), in FW and SW. Also, Na+/K+ − ATPase subunit alpha 1b (nkaα1b), occludin (ocln), and prolactin receptor (prlr) were upregulated in FW and claudin 15 (cldn15) in SW groups exposed to this photoperiod. The posterior intestine was less responsive to the experimental treatments, although upregulation of nkcc1, nkcc2, slc26a6, and cftrI was observed in FW in the short photoperiod groups. Hence, our findings show that exposure to a winter signal in FW more effectively activates hypo-osmoregulatory mechanisms in the intestine of Atlantic salmon, where a coordinated and complementary role of the anterior and posterior intestine ensures optimal SW processing. Dietary treatment had a positive but more marginal effect on the regulation of the genes investigated, mainly enhancing the impact of short photoperiod when the two treatments were combined. Overall, we propose the apical Na+/K+/2Cl− cotransporter, nkcc2, and the apical Cl−/HCO3− exchanger, slc26a6, as potential FW molecular markers in the anterior intestine to assess “SW-readiness” in Atlantic salmon smolts.

Acromesomelic Dysplasia With Homozygosity for a Likely Pathogenic BMPR1B Variant: Postaxial Polydactyly as a Novel Clinical Finding.

Acromesomelic chondrodysplasias are a rare subgroup of the clinically and genetically heterogeneous osteochondrodysplasias that are characterised by abnormalities in the limb development and short stature. Here, we report a 2-year-old boy, offspring of consanguineous parents, with acromesomelic dysplasia and postaxial polydactyly in which exome sequencing identified a novel homozygous missense variant in BMPR1B. The patient showed skeletal malformation of both hands and feet that included complex brachydactyly with the thumbs most severely affected, postaxial polydactyly of both hands, shortened toes as well as a bilateral hypoplasia of the fibula. Whole trio exome sequencing was conducted to identify potential genetic variants in the patient. The analysis identified the biallelic variant NM_001203.3:c.821A > G;p.(Gln274Arg) in BMPR1B, a gene encoding bone morphogenetic protein receptor 1B. The skeletal phenotype can be brought in line with the phenotypes of previously reported cases of BMPR1B-associated chondrodysplasias. However, the postaxial polydactyly described here is a novel clinical finding in a BMPR1B-related case; notably, it has previously been reported in other acromesomelic dysplasia cases caused by homozygous pathogenic variants in GDF5-a gene which encodes for growth differentiation factor 5, a high-affinity ligand to BMPR1B.

Phytol exerts sedative-like effects and modulates the diazepam and flumazenil’s action, possibly through the GABAA receptor interaction pathway

This study aimed at the evaluation of the sedative effect of phytol (PHY) with possible molecular mechanisms through in vivo and in silico studies. For this, adult male mice were randomly divided into six individual groups, namely control (vehicle), two standards (DZP: diazepam at 2 m/kg, FLU: flumazenil at 0.1 mg/kg), three test groups (PHY at 25, 50, and 75 mg/kg), and three combined groups with the DZP-2 and/or FLU-0.1 with PHY-75 mg/kg. After thirty minutes, each animal was treated with thiopental sodium (TS) at 40 mg/kg to produce sedation and observed for latency and duration of sleep up to 4 h. In silico studies were performed with the 6X3X protein of the GABAA receptor α1 and β2 subunits. The results demonstrate that PHY dose-dependently enhanced sleep duration in animals. However, it produced an insignificant sleep duration compared to the control and standard groups. It also significantly (p < 0.05) decreased the latency and increased the duration of sleep with DZP-2, while reducing these parameters with FLU-0.1. In in silico studies, DZP and FLU exhibited binding affinities with 6X3X by −6.8 and −6.9 kcal/mol, respectively, while PHY exhibited −6.9 kcal/mol. Taken together, PHY may exert a sedative-like effect in TS-induced sleeping mice and modulate the effects of DZP and FLU, possibly through interacting with the 6X3X protein of the GABAA receptor. PHY may be one of the good candidates for the management of sleep disturbances, such as insomnia.