Receptor Type Research Articles

MS4A superfamily molecules in tumors, Alzheimer’s and autoimmune diseases

MS4A (membrane-spanning 4-domain, subfamily A) molecules are categorized into tetraspanins, which possess four-transmembrane structures. To date, eighteen MS4A members have been identified in humans, whereas twenty-three different molecules have been identified in mice. MS4A proteins are selectively expressed on the surfaces of various immune cells, such as B cells (MS4A1), mast cells (MS4A2), macrophages (MS4A4A), Foxp3+CD4+ regulatory T cells (MS4A4B), and type 3 innate lymphoid cells (TMEM176A and TMEM176B). Early research confirmed that most MS4A molecules function as ion channels that regulate the transport of calcium ions. Recent studies have revealed that some MS4A proteins also function as chaperones that interact with various immune molecules, such as pattern recognition receptors and/or immunoglobulin receptors, to form immune complexes and transmit downstream signals, leading to cell activation, growth, and development. Evidence from preclinical animal models and human genetic studies suggests that the MS4A superfamily plays critical roles in the pathogenesis of various diseases, including cancer, infection, allergies, neurodegenerative diseases and autoimmune diseases. We review recent progress in this field and focus on elucidating the molecular mechanisms by which different MS4A molecules regulate the progression of tumors, Alzheimer’s disease, and autoimmune diseases. Therefore, in-depth research into MS4A superfamily members may clarify their ability to act as candidate biomarkers and therapeutic targets for these diseases. Eighteen distinct members of the MS4A (membrane-spanning four-domain subfamily A) superfamily of four-transmembrane proteins have been identified in humans, whereas the MS4A genes are translated into twenty-three different molecules in mice. These proteins are selectively expressed on the surface of various immune cells, such as B cells (MS4A1), macrophages (MS4A4A), mast cells (MS4A2), Foxp3+CD4+ regulatory T cells (MS4A4B), type 3 innate lymphoid cells (TMEM176A and TMEM176B) and colonic epithelial cells (MS4A12). Functionally, most MS4A molecules function as ion channels that regulate the flow of calcium ions [Ca2+] across cell membranes. Recent studies have revealed that some MS4A proteins also act as molecular chaperones and interact with various types of immune receptors, including pattern recognition receptors (PRRs) and immunoglobulin receptors (IgRs), to form signaling complexes, thereby modulating intracellular signaling and cellular activity. Evidence from preclinical animal models and human genetic studies suggests that MS4A proteins play critical roles in various diseases (2). Therefore, we reviewed the recent progress in understanding the role of the MS4A superfamily in diseases, particularly in elucidating its function as a candidate biomarker and therapeutic target for cancer.

Anemia in Myelofibrosis: A Focus on Proactive Management and the Role of Momelotinib

Background: Anemia is a common and progressive clinical manifestation of myelofibrosis that may occur as part of the disease pathogenesis as well as due to the myelosuppressive effects of some treatments, with a substantial impact on quality of life, prognosis, and healthcare resource utilization. Despite these burdens, anemia management has traditionally been a secondary priority to spleen and symptom control, due in part to the limitations of available therapeutic approaches. With the initial regulatory approvals of momelotinib, a Janus kinase 1 (JAK1), JAK2, and activin A receptor type 1 inhibitor that provides anemia-related benefits in addition to addressing splenomegaly and symptoms, re-evaluation of anemia as an early and prominent treatment consideration is warranted. Methods: In this review, we discuss the journey of patients with myelofibrosis and anemia across various severities and clinical scenarios. Results: Summarized are traditional approaches to anemia management and the clinical trial efficacy and safety data that support momelotinib as an option in each setting from mild to severe anemia, including in the context of co-occurring thrombocytopenia. Conclusions: With the availability of momelotinib and other emerging therapies directed at anemia control, early treatment of anemia to avoid progression and support improvement in eligible patients with myelofibrosis should be a primary consideration.

Histological assessments for anabolic effects in teriparatide/abaloparatide administered rodent models.

Parathyroid hormone (PTH) is thought to induce remodeling-based bone formation by promoting osteoclastic activity, a process known as cellular coupling. Our research has shown that the frequency of PTH administration affects trabecular number and thickness. High-frequency PTH administration induced remodeling-based bone formation, while less frequent administration induced both remodeling-based and modeling-based bone formation. Additionally, we found that specific bone sites influence whether remodeling-based or modeling-based bone formation is more likely to occur. Additionally, while PTH significantly increases trabecular bone, it also causes cortical porosis. Our research on the femoral diaphysis showed that PTH administration resulted in the invasion of blood vessels and osteoclasts into the cortical bone. Abaloparatide acts similarly to teriparatide through the parathyroid hormone receptor type 1 (PTH1R) but may have a wider anabolic window due to its lesser impact on bone resorption. Our mouse studies with abaloparatide showed similar results to those seen in human patients, with increased preosteoblastic cell populations and wider anabolic windows when compared with teriparatide. Abaloparatide-induced bone formation cannot be explained solely by remodeling-based bone formation, indicating the need for further research into modeling-based bone formation.

Somatostatin Receptor Imaging in the Diagnosis and Management of Parathyroid Neuroendocrine Neoplasia

Background: Parathyroid tumors are classified as parathyroid neuroendocrine neoplasia (NEN) by the IARC-WHO classification. These tumors can occur with NENs from other sites, which often require total-body [68Ga]-DOTA-peptides PET/CT. This study aimed to assess the utility of [68Ga]-DOTA-peptide PET/CT in imaging parathyroid NENs and to evaluate the underlying mechanisms. Methods: Fifty patients with primary hyperparathyroidism (PHPT) and parathyroid NENs histologically confirmed as parathyroid adenomas (PAs) were included. PET/CT with [68Ga]-DOTA-peptide was performed in 16 patients with localized PAs, including 10 with MEN1 syndrome. Somatostatin receptor types 2 and 5 (SST2 and SST5) staining was performed on PAs from 48 patients. Somatostatin analogs (SSA) were prescribed in four patients with MEN 1 syndrome and 1 with persistent acromegaly, all with PAs and PHPT. The therapy effects on calcium and parathyroid hormone (iPTH) were evaluated. Results: [68Ga]-DOTA-peptide PET/CT detected 20 PAs with high radiopharmaceutical uptake. SST2 expression was negative on PA cell membranes in all cases and positive on endothelium in 39 (81%) PAs. Membrane SST5 expression was positive in 25 (52%) PAs and endothelial was positive in 40 (83%). Serum calcium levels decreased in patients on SSA therapy, while iPTH did not. Conclusions: PET/CT with [68Ga]-DOTA-peptides can detect parathyroid NENs. The incidental detection of high [68Ga]-DOTA-peptide uptake in the parathyroid region during whole-body PET/CT may prompt biochemical evaluation for PHPT. We suggest that endothelial SST expression mediates high radiopharmaceutical uptake by PAs and that SSA treatment can reduce hypercalcemia in PHPT patients.

Structural plasticity of arrestin-G protein coupled receptor complexes as a molecular determinant of signaling

G protein coupled receptors (GPCRs) are critically regulated by arrestins. In this study, high-resolution data was combined with molecular dynamics simulations to infer the determinants of β-arrestin 1 (βarr1)-GPCR coupling, using the V2 vasopressin receptor (V2R) as a model system.The study highlighted the extremely high plasticity of βarr1-GPCR complexes, dependent on receptor type, state, and membrane environment. The multiple functions of receptor-bound βarr1 are likely determined by the interplay of intrinsic flexibility and collective motions both as a bi-domain protein and as a whole. The two major collective motions of the whole βarr1, consisting in rotation parallel to the membrane plane and inclination with respect to the receptor main axis, are distinctly linked to the two intermolecular interfaces involved in tail and core interactions.The intermolecular dynamic coupling between βarr1 and V2R depends on the allosteric effect of the agonist arginine-vasopressin (AVP). In the absence of AVP the dynamic coupling concerns only tail interactions, while in the presence of AVP it involves both tail and core interactions. This suggests that constitutive and agonist-induced arrestin-receptor dynamic coupling is linked to distinct arrestin functions.

Oxygen-controllable injectable hydrogel alleviates intervertebral disc degeneration by balancing extracellular matrix metabolism

Nucleus pulposus (NP) cells, situated at the core of intervertebral discs, have acclimated to a hypoxic environment, orchestrating the equilibrium of extracellular matrix metabolism (ECM) under the regulatory influence of hypoxia inducible factor-1α (HIF-1α). Neovascularization and increased oxygen content pose a threat, triggering ECM degradation and intervertebral disc degeneration (IVDD). To address this, our study devised an oxygen-controllable strategy, introducing laccase into an injectable and ultrasound-responsive gelatin/agarose hydrogel. Laccase-mediated reactions were employed to deplete oxygen, establishing a hypoxic microenvironment that upregulated HIF-1α expression. The activation of hypoxia-inducible factors significantly enhanced the expression of aggrecan and collagen II, concurrently suppressing Matrix metalloproteinases (MMP13) and A Disintegrin and Metalloproteinase with Thrombospondin motifs (ADAMTS5) levels, thereby restoring the equilibrium of ECM metabolism. Simultaneously, the hydrogel facilitated the recruitment of stem cells into the NP through the controlled release of ATI2341, activating C-X-C chemokine receptor type 4 (CXCR4). Moreover, ultrasound amplification enhanced ATI2341 release, promoting the migration of NP stem cells. The hydrogel's efficacy in mitigating metabolic imbalances and inhibiting IVDD progression was substantiated in a rat puncture IVDD model through hydrogel injection into the discs. In conclusion, this hypoxia-inducible hydrogel, responsive to thermal stimuli from ultrasound, presents a promising avenue for IVDD treatment.

HER-2 expression is correlated with multimodal imaging features in breast cancer: a pilot study

Objective A pilot study to evaluate the correlation between multimodal imaging features and the expression of the human epidermal growth factor receptor type 2 (HER-2) in breast cancer to provide a basis for clinical treatment and prognosis evaluation. Methods We included a total of 62 patients with breast cancer admitted to the Affiliated Hospital of Hebei University between 2018 and 2022. All of them underwent the relevant investigations, including ultrasound, mammography, and enhanced magnetic resonance imaging (MRI), in the hospital within one month before surgery or biopsy. HER-2 expression level was divided into negative and positive by immunohistochemistry(IHC). Using SPSS 24.0 statistical software to analyze the differences in imaging features between the HER-2 positive and the HER-2 negative groups. Results There was a statistically significant difference between the HER-2 positive and the HER-2 negative groups (p = 0.005) in the hyperechoic halo sign around the lesion detected by ultrasonography as well as in the apparent diffusion coefficient (ADC) on MRI (p = 0.047). The sensitivity and specificity of the hyperechoic halo sign in predicting HER-2 positivity was 48.3% and 84.8% respectively, and the area under the curve (AUC) for the ADC value to predict HER-2 expression was 0.533. When b was equal to 800 and the ADC value (cutoff value) was 0.000888 mm2/s, the sensitivity and specificity were 65.5% and 51.5%, respectively. Conclusion A combination of multimodal imaging features and HER-2 gene expression can provide more valuable information for clinical diagnosis and therapeutic schedule in breast cancer.

Therapeutic potential of agents targeting cannabinoid type 2 receptors in organ fibrosis.

The endocannabinoid system has garnered attention as a potential therapeutic target in a range of pathological disorders. Cannabinoid receptors type 2 (CB2) are a class of G protein-coupled receptors responsible for transmitting intracellular signals triggered by both endogenous and exogenous cannabinoids, including those derived from plants (phytocannabinoids) or manufactured synthetically (synthetic cannabinoids). Recent recognition of the role of CB2 receptors in fibrosis has fueled interest in therapeutic targeting of CB2 receptors in fibrosis. Fibrosis is characterized by the alteration of the typical cellular composition within the tissue parenchyma, resulting from exposure to diverse etiological factors. The pivotal function of CB2 agonists has been widely recognized in the regulation of inflammation, fibrogenesis, and various other biological pathologies. The modulation of CB2 receptors, whether by enhancing their expression or activating their function, has the potential to provide benefits in numerous conditions, particularly by avoiding any associated adverse effects on the central nervous system. The sufficient activation of CB2 receptors resulted in the complete suppression of gene expression related to transforming growth factor β1 and its subsequent fibrogenic response. Multiple reports have also indicated the diverse functions that CB2 agonists possess in mitigating chronic inflammation and subsequent fibrosis development in various types of tissues. While currently in the preclinical stage, the advancement of CB2 compounds has garnered significant attention within the realm of drug discovery. This review presents a comprehensive synthesis of various independent experimental studies elucidating the pivotal role of identified natural and synthetic CB2 agonists in the pathophysiology of organ fibrosis, specifically in the cardiac, hepatic, and renal systems.

Deciphering the Interlinked CXCR4-Mediated Feedback Loop Among Signaling Pathways in Diabetic Wound Healing

Abstract: Diabetic chronic wounds and amputations are very serious complications of diabetes mellitus (DM) that result from an integration factor, including oxygen deprivation, elevated reactive oxygen species (ROS), reduced angiogenesis, and microbial invasion. These causative factors lead to tenacious wounds in an inflammatory state, which eventually results in tissue aging and necrosis. Wound healing in DM potentially targets C-X-C chemokine receptor type 4 (CXCR4) regulates several signalling pathways. The CXCR4 signalling pathway integrated with phospholipase C (PLC)/protein kinase-C (PKC) Ca2+ pathways, stromal cell-derived factor-1 (SDF-1), and mitogen- activated protein kinases (MAPKs) pathway for enhancing cell chemotaxis, proliferation, and survival. The dysregulated CXCR4 pathway is connected with poor wound healing in DM patients. Therapeutic strategies targeting CXCR4-based molecules such as UCUF-728, UCUF-965, and AMD3100 have been shown to enhance diabetic wound healing by altering miRNA expression, promoting angiogenesis, and accelerating wound closure. This study indicates that CXCR4 participation in various signalling pathways makes it essential for Understanding the healing of diabetic wounds. Using specific compounds to target CXCR4 offers a potentially effective treatment strategy to improve wound healing in diabetes. Our understanding of CXCR4 signalling and its regulation processes will enable us to develop more potent wound care solutions for diabetic chronic wounds. This report concludes that CXCR4's potential therapeutic targeting shows improvements in diabetic wound repair. This review will demonstrate that CXCR4 plays a major role in wound healing through its various signalling pathways. Targeting CXCR4 with certain agonist molecules shows a therapeutic approach to potentially increasing wound healing in diabetes. By enhancing our understanding of the CXCR4 signalling mechanism in future studies, we can develop more potential treatments for chronic diabetic wounds.

Late relapse of anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis: a case report

BackgroundAnti-N-methyl-d-aspartate receptor encephalitis is a sporadic autoimmune disorder of the brain that presents in a variety of neuropsychiatric manifestations, including seizures, psychosis, and alterations in behavior. N-methyl-d-aspartate receptor is primarily seen in young females. Although this disease can be treated, it can relapse in rare cases. Relapsing typically occurs within the early years following the initial episode and is exceedingly rare after 5 years.Case presentationIn this case study, we report on a 16-year-old Iranian female experiencing a relapse of anti-N-methyl-d-aspartate receptor encephalitis 8 years after her initial diagnosis. She was admitted to the hospital with dysphasia (a speech disorder) and dyslexia (reading and writing impairment). A thorough clinical evaluation revealed the presence of anti-glutamate receptor type N-methyl-d-aspartate receptor antibodies in her serum and cerebrospinal fluid, confirming the diagnosis. Following treatment with immunotherapy and plasmapheresis, she made a complete recovery.ConclusionThis case of relapsing anti-N-methyl-d-aspartate receptor encephalitis, occurring more than 5 years after the initial episode, is exceptionally rare. This late relapse underscores the importance of long-term follow-up for patients with this condition.

Binding of Infectious Hypodermal and Haematopoietic Necrosis Virus-Like Particles to Mannose Receptor Stimulates Antimicrobial Responses in Immune-Related Tissues of Peneaus vannamei.

Mannose receptor (MR) is a transmembrane protein and a type of pattern-recognition receptor (PRR) that plays a critical role in the immunity of mammals and fish. In this study, we examined the role of MR in binding with infectious hypodermal and haematopoietic necrosis virus-like particle (IHHN-VLP) and the downstream immune pathway that it triggers in the shrimp Peneaus vannamei. Upon IHHN-VLP challenge, transcripts of MR in P. vannamei (PvMR) increased significantly in all examined tissues, particularly those related to shrimp immunity, including hemocyte, hepatopancreas and gill tissues. Specifically, IHHN-VLP bound to the 34-kDa PvMR protein in shrimp-tissue extracts. Immunohistochemistry results of hemocytes showed that PvMR was initially localised on the plasma membrane but later internalised and dispersed throughout the cytoplasm after IHHN-VLP administration. Binding between IHHN-VLP and PvMR also induced significant upregulation of genes for the antimicrobial peptides (AMPs) penaeidin 3 and crustin, presumably to protect the shrimp against the viral infection. However, knocking down PvMR resulted in down-regulation of all immune-related genes examined. Overall, as an immune-related PRR, PvMR serves as a receptor for invading viruses, which then trigger the expression of AMPs. Strategic designs using PvMR could be developed to either block the interaction of native virus with the host cells or provoke its up-regulation to enhance shrimp immunity, which could open up opportunities to fight against IHHNV infection in shrimp.

Alpha-synuclein Fibrils Inhibit Activation of the BDNF/ERK Signaling Loop in the mPFC to Induce Parkinson's Disease-like Alterations with Depression.

Depression (Dep) is one of the most common concomitant symptoms of Parkinson's disease (PD), but there is a lack of detailed pathologic evidence for the occurrence of PD-Dep. Currently, the management of symptoms from both conditions using conventional pharmacological interventions remains a formidable task. In this study, we found impaired activation of extracellular signal-related kinase (ERK), reduced levels of transcription and translation, and decreased expression of brain-derived neurotrophic factor (BDNF) in the medial prefrontal cortex (mPFC) of PD-Dep rats. We demonstrated that the abnormal phosphorylation of α-synuclein (pS129) induced tropomyosin-related kinase receptor type B (TrkB) retention at the neuronal cell membrane, leading to BDNF/TrkB signaling dysfunction. We chose SEW2871 as an ameliorator to upregulate ERK phosphorylation. The results showed that PD-Dep rats exhibited improvement in behavioral manifestations of PD and depression. In addition, a reduction in pS129 was accompanied by a restoration of the function of the BDNF/ERK signaling loop in the mPFC of PD-Dep rats.

On m-Negative Sets and Out Mondirected Topologies in the Human Nervous System

Using the monophonic paths in the theory of directed graphs, this paper constructs a new topology called the out mondirected topology, which characterizes the graphs that induce indiscrete or discrete topology. We give and study some of the relations and properties, such as the relationship between the isomorphic relation, in directed graphs and the homeomorphic property in out mondirected topological spaces, compactness, D±-connectedness, connectedness and D±-discrete properties. Finally, we apply our results of out mondirected topological spaces in the nervous system of the human body, such as in the messenger signal network, in diagrams of sensory neuron cells and in models of two distinct nicotinic receptor types based on the second messenger signal.

An in vivo examination of the relationship between metabotropic glutamate receptor 5 and suicide attempts in people with borderline personality disorder

BackgroundBorderline Personality Disorder (BPD) is a serious psychiatric condition, associated with a high risk for suicide attempts and death by suicide. However, relatively little is known about the pathophysiology of BPD. The metabotropic glutamate receptor type 5 (mGlu5) has been specifically implicated in the pathophysiology of BPD and suicide attempts, with more general roles in emotion regulation, social and cognitive functioning, and pain processing. Here, we examined the relationship between mGlu5 availability, BPD, and suicide attempts in vivo for the first time. MethodsEighteen individuals with BPD, and 18 age-, sex-, and smoking-status matched healthy (HC) and 18 clinical comparison controls with major depressive disorder (MDD) completed comprehensive clinical assessments and participated in an [18F]FPEB positron emission tomography (PET) scan to measure mGlu5 availability. Volume of distribution (VT) in the frontolimbic circuit implicated in BPD pathophysiology was the PET outcome measure. ResultsWe observed significantly higher frontolimbic mGlu5 availability in BPD compared to both HC (p=.009, d=0.84, 18.43% difference), and MDD (p=.03, d=0.69, 15.21% difference). In the BPD, but not MDD group, higher mGlu5 availability was also associated with history of suicide attempts (SA; 19-25% higher, p’s=.005-.02). Further, mGlu5 availability was positively correlated with risk factors for suicide (e.g., sexual victimization, perceived burdensomeness) in BPD-SA group. ConclusionsResults show higher mGlu5 availability in BPD and suicide attempt for the first time. Our preliminary findings suggest mGlu5 may be a critical treatment target for BPD symptoms, including suicide attempts, and warrant further investigation in larger samples.

Microglial cannabinoid receptor type II stimulation improves cognitive impairment and neuroinflammation in Alzheimer's disease mice by controlling astrocyte activation.

Alzheimer's disease (AD) is the most common form of dementia and is characterized by the accumulation of amyloid β (Aβ) and phosphorylated tau. Neuroinflammation, mainly mediated by glial activation, plays an important role in AD progression. Although there is growing evidence for the anti-neuroinflammatory and neuroprotective effects of the cannabinoid system modulation, the detailed mechanism remains unclear. To address these issues, we analyzed the expression levels of cannabinoid receptor type II (Cnr2/Cb2) in AppNL-G-F/NL-G-F mice and human AD precuneus, which is vulnerable to amyloid deposition in AD, and the effects of JWH 133, a selective CB2 agonist, on neuroinflammation in primary glial cells and neuroinflammation and cognitive impairment in AppNL-G-F/NL-G-F mice. The levels of Cnr2/Cb2 were upregulated in microglia isolated from the cerebral cortex of AppNL-G-F/NL-G-F mice. CNR2 expression was also increased in RNAs derived from human precuneus with advanced AD pathology. Chronic oral administration of JWH 133 significantly ameliorated the cognitive impairment of AppNL-G-F/NL-G-F mice without neuropsychiatric side effects. Microglia and astrocyte mRNAs were directly isolated from the mouse cerebral cortex by magnetic-activated cell sorting, and the gene expression was determined by quantitative PCR. JWH 133 administration significantly decreased reactive astrocyte markers and microglial C1q, an inducer for the reactive astrocytes in AppNL-G-F/NL-G-F mice. In addition, JWH133 administration inhibited the expression of p-STAT3 (signal transducer and activator of transcription 3) in astrocytes in AppNL-G-F/NL-G-F mice. Furthermore, JWH 133 administration suppressed dystrophic presynaptic terminals surrounding amyloid plaques. In conclusion, stimulation of microglial CB2 ameliorates cognitive dysfunction in AppNL-G-F/NL-G-F mice by controlling astrocyte activation and inducing beneficial neuroinflammation, and our study has implications that CB2 may represent an attractive therapeutic target for the treatment of AD and perhaps other neurodegenerative diseases involving neuroinflammation.

Vibrational spectroscopic characterization, quantum chemical, molecular docking and molecular dynamics investigations of cyclo(L-phenylalanyl-L-proline), an anticancer agent

The molecular structure and spectral properties of cyclo(L-Phenylalanyl-L-Proline) dipeptide, which has several biological activities, were investigated. Firstly, conformational preference of the cyclo(L-Phenylalanyl-L-Proline) was searched and obtained lowest energy conformer of the cyclic dipeptide was then optimized using Density Functional Theory with wb97xd/6-311++G(d,p) level of theory. A detailed vibrational spectral analysis has been carried out and assignments of the fundamental modes have been proposed. The experimental vibrational wavenumbers of the investigated compound display good agreement with the computed values. The Frontier Molecular Orbitals, Molecular Electrostatic Potential and electronic transitions of the investigated compound were discussed. In addition, the 1H and 13C NMR chemical shifts of the cyclic dipeptide were calculated and the results were compared with the experimental values. Also, to evaluate the anticancer potential, molecular docking studies of cyclo(L-Phenylalanyl-L-Proline) within the ATP-binding sites of both wild type (EGFRWT; ID: 4HJO) and mutant (EGFRT790M; ID: 3W2O) Epidermal Growth Factor Receptor were performed. The results indicated that cyclo(Phe-Pro) has high binding affinities toward both EGFRWT (−6.6 kcal/mol) and EGFRT790M (−7.7 kcal/mol) receptors, thus, has good anticancer activity and also has potential to overcome drug resistance in therapy. Molecular dynamics simulations on cyclo(L-Phenylalanyl-L-Proline)-wild type complex were conducted through a 50-nanosecond timed to investigate the ligand-receptor interactions in more detail, and to determine the binding free energy accurately. The binding free energy of the cyclo(L-Phenylalanyl-L-Proline)-wild type complex was calculated to be −27.18 kcal/mol.

Unraveling GPCRs Allosteric Modulation. Cannabinoid 1 Receptor as a Case Study.

G-protein-coupled receptors (GPCRs) constitute one of the most prominent families of integral membrane receptor proteins that mediate most transmembrane signaling processes. Malfunction of these signal transduction processes is one of the underlying causes of many human pathologies (Parkinson's, Huntington's, heart diseases, etc), provoking that GPCRs are the largest family of druggable proteins. However, these receptors have been targeted traditionally by orthosteric ligands, which usually causes side effects due to the simultaneous targeting of homologous receptor subtypes. Allosteric modulation offers a promising alternative approach to circumvent this problematic and, thus, comprehending its details is a most important task. Here we use the Cannabinoid type-1 receptor (CB1R) in trying to shed light on this issue, focusing on positive allosteric modulation. This is done by using the protein-dipole Langevin-dipole (PDLD) within the linear response approximation (LRA) framework (PDLD/S-2000) along with our coarse-grained (CG) model of membrane proteins to evaluate the dissociation constants (KBs) and cooperativity factors (αs) for a diverse series of CB1R positive allosteric modulators belonging to the 2-phenylindole structural class, considering CP55940 as an agonist. The agreement with the experimental data evinces that significantly populated allosteric modulator:CB1R and allosteric modulator:CP55940:CB1R complexes have been identified and characterized successfully. Analyzing them, it has been determined that CB1R positive allosteric modulation lies in an outwards displacement of transmembrane α helix (TM) 4 extracellular end and in the regulation of the range of motion of a compound TM7 movement for binary and ternary complexes, respectively. In this respect, we achieved a better comprehension of the molecular architecture of CB1R positive allosteric site, identifying Lys1923.28 and Gly1943.30 as key residues regarding electrostatic interactions inside this cavity, and to rationalize (at both structural and molecular level) the exhibited stereoselectivity in relation to positive allosteric modulation activity by considered CB1R allosteric modulators. Additionally, putative/postulated allosteric binding sites have been screened successfully, identifying the real CB1R positive allosteric site, and most structure-activity relationship (SAR) studies of CB1R 2-phenylindole allosteric modulators have been rationalized. All these findings point out towards the predictive value of the methodology used in the current work, which can be applied to other biophysical systems of interest. The results presented in this study contribute significantly to understand GPCRs allosteric modulation and, hopefully, will encourage a more thorough exploration of the topic.

Mesenchymal stem cells treated with Interleukin-1 beta for mediation of an inflammatory response in human tissues.

The present study examined the functional activities of the human bone marrow mesenchymal stem cells (hBM-MSCs) under the effects of various concentrations of the inflammatory mediator interleukin 1 beta (IL-1β). The effects of IL-1β on the functional properties of hBM-MSCs were measured using functional assays (adhesion, proliferation, and migration). hBM-MSCs expressions of colony-stimulating factors 1 and 2 (CSF1, CSF2), C-C chemokine receptor type 2 (CCR2), C-X-C chemokine receptor type 1 and 3 (CXCL1, CXCL3), were examined using real-time polymerase chain reaction (RT‒PCR). The pro-inflammatory cytokine IL-1β did not disrupt hBM-MSCs adhesion, but it improved proliferation and migration only up to 50 ng/ml. However, in response to 100 ng/ml IL-1β, cell growth, proliferation, and migration were reduced significantly. The expression of CSF1, CCR2, CXCL3, and IL-1β genes increased with the increase in the concentration of IL-1β. CSF2 and CXCL1 gene expression increased in the 50ng/ml group compared with the 10ng/ml group to be higher than the control group in the 100ng/ml IL-1β group which might facilitate the differentiation, and homing of MSCs to the site of injury and augment their activities in the inflamed microenvironment. The study corroborates the advantages of prior stimulation of mesenchymal stem cells (MSCs) with the cytokine IL-1β, demonstrating an upregulation of key chemokines and cytokines. This upregulation potentially enhances MSCs' ability to differentiate and migrate to injury sites, while also augmenting their functional role within an inflamed microenvironment, thereby amplifying their therapeutic potential.

C-terminal tagging enhances the detection sensitivity of interlekin receptor type 1.

Substances released outside of the cells during cell necrosis are collectively called danger-associated molecular patterns (DAMPS) or alarmins. A pro-inflammatory cytokine, interleukin-1α (IL-1α) is known as a typical alarmin. IL-1α transmits signals by binding to IL-1 receptor 1 (IL-1R1), type I protein, expressed on the cell membrane of target cells, but detection of IL-1R1 at the protein and mRNA levels is difficult. Although the reasons are not elucidated, we attempted to add the HiBiT-tag to the N-terminus (N'-R1) or C-terminus (C'-R1) of IL-1R1 to examine whether the detection sensitivity can be augmented. Increase in detection sensitivity will allow the investigation of its function and subcellular localization much further. Using uterine cervical cancer-derived HeLa cells and its derivative CR-R1-4 cells lacking IL-1R1, C'-R1 was demonstrated to significantly increase the detection sensitivity of IL-1R1. Furthermore, the signal transduction function of neither N'-R1 nor C'-R1 was affected. Immunofluorescence cell staining revealed that wild-type IL-1R1 is mainly localized in the nucleus, whereas C'-R1 is localized both in the nucleus and the cytoplasm. The above results showed that adding a tag to the C-terminus of IL-1R1 increases detection sensitivity while maintaining its function. In the future, we would like to further investigate the relationship between changes in the intracellular localization of C'-R1 and increases in detection sensitivity.

The cannabinoid CB2 receptor positive allosteric modulator EC21a exhibits complicated pharmacology in vitro

Schizophrenia is a complex disease involving the dysregulation of numerous brain circuits and patients exhibit positive symptoms (hallucinations, delusions), negative symptoms (anhedonia), and cognitive impairments. We have shown that the antipsychotic efficacy of positive allosteric modulators (PAMs) of both the M4 muscarinic receptor and metabotropic glutamate receptor 1 (mGlu1) involve the retrograde activation of the presynaptic cannabinoid type-2 (CB2) receptor, indicating that CB2 activation or potentiation could result in a novel therapeutic strategy for schizophrenia. We used two complementary assays, receptor-mediated phosphoinositide hydrolysis and GIRK channel activation, to characterize a CB2 PAM scaffold, represented by the compound EC21a, to explore its potential as a starting point to optimize therapeutics for schizophrenia. These studies revealed that EC21a acts as an allosteric inverse agonist at CB2 in both assays and exhibits a mixed allosteric agonist/negative allosteric modulator profile at CB1 depending upon the assay used for profiling. A series of compounds related to EC21a also functioned as CB2 inverse agonists. Overall, these results suggest that EC21a exhibits complicated and potentially assay-dependent pharmacology, which may impact interpretation of in vivo studies.