{"title":"Retraction: Endothelial-monocyte activating polypeptide II suppresses the <i>in vitro</i> glioblastoma-induced angiogenesis by inducing autophagy.","authors":"","doi":"10.3389/fnmol.2024.1543503","DOIUrl":"https://doi.org/10.3389/fnmol.2024.1543503","url":null,"abstract":"<p><p>[This retracts the article DOI: 10.3389/fnmol.2017.00208.].</p>","PeriodicalId":12630,"journal":{"name":"Frontiers in Molecular Neuroscience","volume":"17 ","pages":"1543503"},"PeriodicalIF":3.5,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11689653/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142914616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Sensory innervation in the prostate and a role for calcitonin gene-related peptide in prostatic epithelial proliferation.","authors":"Hanyu Xia, Travis J Jerde, Jill C Fehrenbacher","doi":"10.3389/fnmol.2024.1497735","DOIUrl":"10.3389/fnmol.2024.1497735","url":null,"abstract":"<p><strong>Introduction: </strong>The prostate is densely innervated like many visceral organs and glands. However, studies to date have focused on sympathetic and parasympathetic nerves and little attention has been given to the presence or function of sensory nerves in the prostate. Recent studies have highlighted a role for sensory nerves beyond perception of noxious stimuli, as anterograde release of neuropeptides from sensory nerves can affect vascular tone and local immune responses.</p><p><strong>Methods: </strong>To identify the degree of sensory innervation in the prostate, we utilized state-of-the-art tissue clearing and microscopy to visualize sensory innervation in the different lobes of the mouse prostate. To determine whether sensory nerves have a role in regulating proliferation within the prostate, we used an intersectional genetic and toxin approach to ablate peptidergic sensory nerves systemically.</p><p><strong>Results: </strong>We found that sensory neurons are abundant in the prostate both in nerve bundles along the vasculature and as independent nerve fibers wrapped around prostatic acini in a net-like fashion. In addition to the dense innervation of the prostate, we found that <i>Calca</i> haploinsufficiency, the genotype control for our intersectional ablation model, results in a diminished level of Ki67 staining in the stromal compartment of the dorsal lobe and a diminishing Ki67 trend in other lobes.</p><p><strong>Discussion: </strong>These findings suggest that sensory neurons might have developmental or homeostatic effects within the prostate. Further studies are warranted to assess the role of sensory neurons and the sensory neuropeptides on prostatic development and on proliferation in the presence of pro-inflammatory stimuli such as bacterial infection or tumor cells.</p>","PeriodicalId":12630,"journal":{"name":"Frontiers in Molecular Neuroscience","volume":"17 ","pages":"1497735"},"PeriodicalIF":3.5,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11688385/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142914617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Insights into the molecular underlying mechanisms and therapeutic potential of endoplasmic reticulum stress in sensorineural hearing loss.","authors":"Guanzhen Li, Huiming Yang, Peiyuan Zhang, Yan Guo, Lili Yuan, Shujiao Xu, Yingxue Yuan, Huabao Xiong, Haiyan Yin","doi":"10.3389/fnmol.2024.1443401","DOIUrl":"10.3389/fnmol.2024.1443401","url":null,"abstract":"<p><p>Sensorineural hearing loss (SNHL) is characterized by a compromised cochlear perception of sound waves. Major risk factors for SNHL include genetic mutations, exposure to noise, ototoxic medications, and the aging process. Previous research has demonstrated that inflammation, oxidative stress, apoptosis, and autophagy, which are detrimental to inner ear cells, contribute to the pathogenesis of SNHL; however, the precise mechanisms remain inadequately understood. The endoplasmic reticulum (ER) plays a key role in various cellular processes, including protein synthesis, folding, lipid synthesis, cellular calcium and redox homeostasis, and its homeostatic balance is essential to maintain normal cellular function. Accumulation of unfolded or misfolded proteins in the ER leads to endoplasmic reticulum stress (ERS) and activates the unfolded protein response (UPR) signaling pathway. The adaptive UPR has the potential to reestablish protein homeostasis, whereas the maladaptive UPR, associated with inflammation, oxidative stress, apoptosis, and autophagy, can lead to cellular damage and death. Recent evidence increasingly supports the notion that ERS-mediated cellular damage responses play a crucial role in the initiation and progression of various SNHLs. This article reviews the research advancements on ERS in SNHL, with the aim of elucidating molecular biological mechanisms underlying ERS in SNHL and providing novel insights for the treatment.</p>","PeriodicalId":12630,"journal":{"name":"Frontiers in Molecular Neuroscience","volume":"17 ","pages":"1443401"},"PeriodicalIF":3.5,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11688397/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142914615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bárbara Guerra Leal, Cláudia Carvalho, Cristina Santos, Raquel Samões, Ricardo Martins-Ferreira, Catarina Teixeira, Diana Rodrigues, Joel Freitas, Carolina Lemos, Rui Chorão, João Ramalheira, João Lopes, António Martins da Silva, Paulo Pinho E Costa, João Chaves
{"title":"Circulating miR-134 in mesial temporal lobe epilepsy: implications in hippocampal sclerosis development and drug resistance.","authors":"Bárbara Guerra Leal, Cláudia Carvalho, Cristina Santos, Raquel Samões, Ricardo Martins-Ferreira, Catarina Teixeira, Diana Rodrigues, Joel Freitas, Carolina Lemos, Rui Chorão, João Ramalheira, João Lopes, António Martins da Silva, Paulo Pinho E Costa, João Chaves","doi":"10.3389/fnmol.2024.1512860","DOIUrl":"10.3389/fnmol.2024.1512860","url":null,"abstract":"","PeriodicalId":12630,"journal":{"name":"Frontiers in Molecular Neuroscience","volume":"17 ","pages":"1512860"},"PeriodicalIF":3.5,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11688299/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142914614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anna Berezovskaia, Morgan Thomsen, Anders Fink-Jensen, Gitta Wörtwein
{"title":"A sex-specific effect of M<sub>4</sub> muscarinic cholinergic autoreceptor deletion on locomotor stimulation by cocaine and scopolamine.","authors":"Anna Berezovskaia, Morgan Thomsen, Anders Fink-Jensen, Gitta Wörtwein","doi":"10.3389/fnmol.2024.1451010","DOIUrl":"10.3389/fnmol.2024.1451010","url":null,"abstract":"<p><strong>Objective: </strong>Acetylcholine modulates the activity of the direct and indirect pathways within the striatum through interaction with muscarinic M<sub>4</sub> and M<sub>1</sub> receptors. M<sub>4</sub> receptors are uniquely positioned to regulate plasticity within the direct pathway and play a substantial role in reward and addiction-related behaviors. However, the role of M<sub>4</sub> receptors on cholinergic neurons has been less explored. This study aims to fill this gap by addressing the role of M<sub>4</sub> receptors on cholinergic neurons in these behaviors.</p><p><strong>Methods: </strong>To investigate the significance of M<sub>4</sub>-dependent inhibitory signaling in cholinergic neurons we created mutant mice that lack M<sub>4</sub> receptors on cholinergic neurons. Cholinergic neuron-specific depletion was confirmed using <i>in situ</i> hybridization. We aimed to untangle the possible contribution of M<sub>4</sub> autoreceptors to the effects of the global M<sub>4</sub> knockout by examining aspects of basal locomotion and dose-dependent reactivity to the psychostimulant and rewarding properties of cocaine, haloperidol-induced catalepsy, and examined both the anti-cataleptic and locomotion-inducing effects of the non-selective anticholinergic drug scopolamine.</p><p><strong>Results: </strong>Basal phenotype assessment revealed no developmental deficits in knockout mice. Cocaine stimulated locomotion in both genotypes, with no differences observed at lower doses. However, at the highest cocaine dose tested, male knockout mice displayed significantly less activity compared to wild type littermates (<i>p</i> = 0.0084). Behavioral sensitization to cocaine was similar between knockout and wild type mice. Conditioned place preference tests indicated no differences in the rewarding effects of cocaine between genotypes. In food-reinforced operant tasks knockout and wild type mice successfully acquired the tasks with comparable performance results. M<sub>4</sub> receptor depletion did not affect haloperidol-induced catalepsy and scopolamine reversal of catalepsy but attenuated scopolamine-induced locomotion in females (<i>p</i> = 0.04). Our results show that M<sub>4</sub> receptor depletion attenuated the locomotor response to high doses of cocaine in males and scopolamine in females, suggesting sex-specific regulation of cholinergic activity.</p><p><strong>Conclusion: </strong>Depletion of M<sub>4</sub> receptors on cholinergic neurons does not significantly impact basal behavior or cocaine-induced hyperactivity but may modulate the response to high doses of cocaine in male mice and the response to scopolamine in female mice. Overall, our findings suggest that M<sub>4</sub>-dependent autoregulation plays a minor but delicate role in modulating specific behavioral responses to pharmacological challenges, possibly in a sex-dependent manner.</p>","PeriodicalId":12630,"journal":{"name":"Frontiers in Molecular Neuroscience","volume":"17 ","pages":"1451010"},"PeriodicalIF":3.5,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11683150/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142907060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Seung H Jung, Laura K Olsen, Krysten A Jones, Raquel J Moore, Sean W Harshman, Candice N Hatcher-Solis
{"title":"VNS paired with training enhances recognition memory: mechanistic insights from proteomic analysis of the hippocampal synapse.","authors":"Seung H Jung, Laura K Olsen, Krysten A Jones, Raquel J Moore, Sean W Harshman, Candice N Hatcher-Solis","doi":"10.3389/fnmol.2024.1452327","DOIUrl":"10.3389/fnmol.2024.1452327","url":null,"abstract":"<p><strong>Introduction: </strong>Recognition memory, an essential component of cognitive health, can suffer from biological limitations of stress, aging, or neurodegenerative disease. Vagus nerve stimulation (VNS) is a neuromodulation therapy with the potential to improve cognitive function. This study investigated the effectiveness of multiple sessions of VNS to enhance recognition memory in healthy rodents and the underlying cognitive benefits of VNS by proteomic analysis of the synaptosome.</p><p><strong>Methods: </strong>Rats demonstrated VNS-induced recognition memory improvements using a novel object recognition (NOR) task. Using the LC-MS/MS method, roughly 3,000 proteins in the synaptosome of the hippocampus were analyzed.</p><p><strong>Results: </strong>Protein-protein interaction (PPI) enrichment analysis found differentially expressed proteins related to synaptic signaling and neurotransmitter pathways. PPI network analysis identified six unique protein clusters, including a cluster of synaptic signaling related pathways. Using ingenuity pathway analysis (IPA), rapamycin-insensitive companion of mTOR was identified as an upstream regulator of synaptosome changes due to VNS-paired training.</p><p><strong>Discussion: </strong>Based on these results, it is proposed that VNS may mediate cognitive enhancement via increases in glutamatergic signaling and early LTP during the consolidation period, followed by sustained synaptic plasticity via modified post-synaptic receptor expression and dendritic outgrowth. Further investigation is required to determine if VNS is a good candidate to ameliorate cognitive impairment.</p>","PeriodicalId":12630,"journal":{"name":"Frontiers in Molecular Neuroscience","volume":"17 ","pages":"1452327"},"PeriodicalIF":3.5,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11685747/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142913939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Excitatory neuron-prone prion propagation and excitatory neuronal loss in prion-infected mice.","authors":"Temuulen Erdenebat, Yusuke Komatsu, Nozomi Uwamori, Misaki Tanaka, Takashi Hoshika, Takeshi Yamasaki, Ayano Shimakura, Akio Suzuki, Toyotaka Sato, Motohiro Horiuchi","doi":"10.3389/fnmol.2024.1498142","DOIUrl":"10.3389/fnmol.2024.1498142","url":null,"abstract":"<p><p>The accumulation of a disease-specific isoform of prion protein (PrP<sup>Sc</sup>) and histopathological lesions, such as neuronal loss, are unevenly distributed in the brains of humans and animals affected with prion diseases. This distribution varies depending on the diseases and/or the combinations of prion strain and experimental animal. The brain region-dependent distribution of PrP<sup>Sc</sup> and neuropathological lesions suggests a neuronal cell-type-dependent prion propagation and vulnerability to prion infection. However, the underlying mechanism is largely unknown. In this study, we provided evidence that the prion 22L strain propagates more efficiently in excitatory neurons than inhibitory neurons and that excitatory neurons in the thalamus are vulnerable to prion infection. PrP<sup>Sc</sup> accumulation was less intense in the striatum, where GABAergic inhibitory neurons predominate, compared to the cerebral cortex and thalamus, where glutamatergic excitatory neurons are predominant, in mice intracerebrally or intraperitoneally inoculated with the 22L strain. PrP<sup>Sc</sup> stains were observed along the needle track after stereotaxic injection into the striatum, whereas they were also observed away from the needle track in the thalamus. Consistent with inefficient prion propagation in the striatum, the 22L prion propagated more efficiently in glutamatergic neurons than GABAergic neurons in primary neuronal cultures. RNAscope <i>in situ</i> hybridization revealed a decrease in <i>Vglut1</i>- and <i>Vglut2</i>-expressing neurons in the ventral posterolateral nuclei of the thalamus in 22L strain-infected mice, whereas no decrease in <i>Vgat</i>-expressing neurons was observed in the adjacent reticular nucleus, mainly composed of <i>Vgat</i>-expressing interneurons. The excitatory neuron-prone prion propagation and excitatory neuronal loss in 22L strain-infected mice shed light on the neuropathological mechanism of prion diseases.</p>","PeriodicalId":12630,"journal":{"name":"Frontiers in Molecular Neuroscience","volume":"17 ","pages":"1498142"},"PeriodicalIF":3.5,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11669680/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142893938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vladislav Soldatov, Artem Venediktov, Andrei Belykh, Gennadii Piavchenko, Mukhammad David Naimzada, Nastasya Ogneva, Natalia Kartashkina, Olga Bushueva
{"title":"Chaperones vs. oxidative stress in the pathobiology of ischemic stroke.","authors":"Vladislav Soldatov, Artem Venediktov, Andrei Belykh, Gennadii Piavchenko, Mukhammad David Naimzada, Nastasya Ogneva, Natalia Kartashkina, Olga Bushueva","doi":"10.3389/fnmol.2024.1513084","DOIUrl":"10.3389/fnmol.2024.1513084","url":null,"abstract":"<p><p>As many proteins prioritize functionality over constancy of structure, a proteome is the shortest stave in the Liebig's barrel of cell sustainability. In this regard, both prokaryotes and eukaryotes possess abundant machinery supporting the quality of the proteome in healthy and stressful conditions. This machinery, namely chaperones, assists in folding, refolding, and the utilization of client proteins. The functions of chaperones are especially important for brain cells, which are highly sophisticated in terms of structural and functional organization. Molecular chaperones are known to exert beneficial effects in many brain diseases including one of the most threatening and widespread brain pathologies, ischemic stroke. However, whether and how they exert the antioxidant defense in stroke remains unclear. Herein, we discuss the chaperones shown to fight oxidative stress and the mechanisms of their antioxidant action. In ischemic stroke, during intense production of free radicals, molecular chaperones preserve the proteome by interacting with oxidized proteins, regulating imbalanced mitochondrial function, and directly fighting oxidative stress. For instance, cells recruit Hsp60 and Hsp70 to provide proper folding of newly synthesized proteins-these factors are required for early ischemic response and to refold damaged polypeptides. Additionally, Hsp70 upregulates some dedicated antioxidant pathways such as FOXO3 signaling. Small HSPs decrease oxidative stress via attenuation of mitochondrial function through their involvement in the regulation of Nrf- (Hsp22), Akt and Hippo (Hsp27) signaling pathways as well as mitophagy (Hsp27, Hsp22). A similar function has also been proposed for the Sigma-1 receptor, contributing to the regulation of mitochondrial function. Some chaperones can prevent excessive formation of reactive oxygen species whereas Hsp90 is suggested to be responsible for pro-oxidant effects in ischemic stroke. Finally, heat-resistant obscure proteins (Hero) are able to shield client proteins, thus preventing their possible over oxidation.</p>","PeriodicalId":12630,"journal":{"name":"Frontiers in Molecular Neuroscience","volume":"17 ","pages":"1513084"},"PeriodicalIF":3.5,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11668803/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142893937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Development of KCC2 therapeutics to treat neurological disorders.","authors":"Shilpa D Kadam, Shane V Hegarty","doi":"10.3389/fnmol.2024.1503070","DOIUrl":"10.3389/fnmol.2024.1503070","url":null,"abstract":"<p><p>KCC2 is CNS neuron-specific chloride extruder, essential for the establishment and maintenance of the transmembrane chloride gradient, thereby enabling synaptic inhibition within the CNS. Herein, we highlight KCC2 hypofunction as a fundamental and conserved pathology contributing to neuronal circuit excitation/inhibition (E/I) imbalances that underly epilepsies, chronic pain, neuro-developmental/-traumatic/-degenerative/-psychiatric disorders. Indeed, downstream of both acquired and genetic factors, multiple pathologies (e.g., hyperexcitability and inflammation) converge to impair KCC2-dependent inhibition in CNS. When KCC2 hypofunction occurs, affected neurons are disinhibited due to impaired inhibitory responses to GABA/glycine. This causes neuronal hyperexcitability, disinhibition within neuron circuits, and disrupted neurological functions. More recently, KCC2 was identified as a genetically-validated target for epilepsy, intellectual disability, and autism spectrum disorder, and pathogenic mutations in human SLC12A5 gene were linked to psychiatric/mood disorders. The broad therapeutic utility of KCC2-upmodulating drugs relates to its critical role in determining inhibitory activity of GABAergic neurotransmission, a mechanism widely targeted by several drugs. However, in cases of KCC2 hypofunction GABAergic neurotransmission can be depolarizing/excitatory, thereby impairing endogenous neuronal inhibition while also limiting the effectiveness of existing therapeutics targeting/requiring GABAergic pathway inhibition. Several preclinical reports have shown that KCC2 upmodulating treatments rescue and increase the efficacy of anti-seizure and analgesic medications. Thus, a first-in-class KCC2-potentiating therapy would provide a novel mechanism for restoring physiological CNS inhibition and addressing drug resistance in patients with E/I imbalance pathologies. Herein, we discuss progress toward and further work needed to develop the first-in-class KCC2 therapeutics to treat neurological disorder patients.</p>","PeriodicalId":12630,"journal":{"name":"Frontiers in Molecular Neuroscience","volume":"17 ","pages":"1503070"},"PeriodicalIF":3.5,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11666659/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142885709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Igor V Peshenko, Elena V Olshevskaya, Alexander M Dizhoor
{"title":"Calcium-sensor proteins but not bicarbonate ion activate retinal photoreceptor membrane guanylyl cyclase in photoreceptors.","authors":"Igor V Peshenko, Elena V Olshevskaya, Alexander M Dizhoor","doi":"10.3389/fnmol.2024.1509366","DOIUrl":"10.3389/fnmol.2024.1509366","url":null,"abstract":"<p><p>Retinal membrane guanylyl cyclase (RetGC), regulated by guanylyl cyclase activating proteins (GCAPs) via negative calcium-feedback, is one of the most critically important enzymes in vertebrate rod and cone physiology, enabling their sensitivity to light. It was also reported that, similarly to olfactory receptor guanylyl cyclase, bicarbonate anion directly stimulates RetGC activity in photoreceptors as a novel phototransduction-linked regulating factor. We directly tested whether or not RetGC is a bicarbonate-activated enzyme using recombinant human RetGC expressed in HEK293 cells and the native RetGC in mouse retinas. Whereas RetGC in all cases was activated by GCAPs, we found no evidence indicating that bicarbonate can produce direct stimulating effect on RetGC catalytic activity, either basal or GCAP-activated, even at concentrations as high as 100 mM. Instead, near-physiological concentrations of bicarbonate only slightly reduced RetGC activity, whereas concentrations substantially exceeding physiological levels caused a more pronounced reduction of RetGC activity measured in mouse retinas. Our results argue that photoreceptor guanylyl cyclase is not a bicarbonate-stimulated enzyme and rule out the possibility that effects of bicarbonate on photoreceptor physiology are mediated by a direct stimulation of retinal guanylyl cyclase by HCO<sub>3</sub> <sup>-</sup>.</p>","PeriodicalId":12630,"journal":{"name":"Frontiers in Molecular Neuroscience","volume":"17 ","pages":"1509366"},"PeriodicalIF":3.5,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11663931/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142881546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}