Dynamics of AQP4 upon exposure to seropositive patient serum before and after Rituximab therapy in Neuromyelitis Optica: A cell-based study

IGF1R/ARRB1 Mediated Regulation of ERK and cAMP Pathways in Response to Aβ Unfolds Novel Therapeutic Avenue in Alzheimer's Disease

IGF1R/INSR signaling is crucial for understanding Alzheimer's disease (AD) and may aid in the development of potent therapeutic strategies. This study investigated the expression and activity of these receptors and their potential to form functional hybrids in response to amyloid beta (Aβ). IGF1R, INSR, and ARRB1 were found to be upregulated in AD. The propensity for functional hybrid formation was also greater in the presence of Aβ. The association of IGF1R with ARRB1 reached a maximum at 60 min of Aβ treatment, which coincided with increased pERK activity at approximately the same time, indicating the importance of this association in pERK regulation. Knocking down IGF1R, INSR, and ARRB1 independently reduced cAMP, whereas overexpressing IGF1R significantly increased cAMP. Knocking down ARRB1 in IGF1R-overexpressing cells led to a reduction in cAMP, indicating that the interaction of ARRB1 and IGF1R possibly contributes to cAMP dysregulation. Since cAMP plays a crucial role in cognition and memory, alterations in cAMP after receptor hybridization could be significant in AD. Additionally, we noted hyperactivation of MAPK, which is associated with aberrant cellular activity, transcriptional control, and stress pathways. This finding highlights the importance of IGF1R and INSR dysregulation, which plays a major role in addition to conventional RTK signaling through multiple pathways. Here, we focused on the ARRB1 and IGF1R interaction and showed that picropodophyllin (PPP), an IGF1R-specific inhibitor, blocks this interaction and alters the ERK and cAMP status under disease conditions. Cell viability studies further revealed that the PPP substantially improved cell viability in the presence of Aβ. This highlights the role of the PPP in regulating these cascades and opens the arena for further therapeutic development for AD.

Small RNA sequencing of differentiated astrocytoma exposed to NMOSD patient sera reveals perturbations in neurodegenerative signaling

The signaling pathways behind severe astrocytic lysis with Aquaporin4 auto-antibody (AQP4-IgG) seropositivity, and reactive astrocytosis with myelin oligodendrocyte glycoprotein auto-antibody (MOG-IgG) seropositivity, remain largely unexplored in Neuromyelitis optica spectrum disorder (NMOSD), while almost no molecular details being known about double-seronegative (DN) patients. Recent discovery of glial fibrillary acidic protein (GFAP) in DN NMOSD patients' cerebrospinal fluid, akin to AQP4-IgG + ve cases, suggests astrocytopathy. Here, we aim to study small non coding RNA (sncRNA) signature alterations in astrocytes exposed to AQP4-IgG + ve and MOG-IgG + ve patient sera, and their potential resemblance with DN-NMOSD. Next Generation Sequencing (NGS) revealed differential expression of several microRNAs with notable alterations in hsa-miR-6824-3p, hsa-miR-324-5p and hsa-miR-4466 respectively upon sera treatment. Results with DN-NMOSD patient sera are majorly similar to that of AQP4+ve sera. Strikingly, in all three treatments, hsa-miR-200b-3p was significantly upregulated. Functional enrichment analysis revealed that Hippo and FoxO signaling pathways were primarily impacted in AQP4-IgG + ve and double negative sera treated cells whereas, MOG-IgG + ve sera treatment perturbed the PI3K-Akt and MAPK signaling pathways. Furthermore, NGS also revealed differential expression of several piRNAs in cells upon treatment with AQP4-IgG + ve and MOG-IgG + ve sera and VEGF signaling was identified as the common target of differentially expressed piRNAs of both the groups. This study, for the first time, revealed that the molecular pathophysiology of double-seronegative NMOSD might involve astrocytopathy akin to AQP4+ve NMOSD, thus pointing towards the possible existence of unidentified astrocytic autoimmune targets and identified the major alterations in intracellular sncRNAs and the associated overall cellular signaling pathways that potentially contribute to the fate of astrocytes during the progression of the disease.

The receptor tyrosine kinase IGF1R and its associated GPCRs are co-regulated by the noncoding RNA NEAT1 in Alzheimer's disease

The study is based on the complexity of Insulin like growth factor receptor (IGF1R) signaling and its regulation by noncoding RNAs (ncRNAs). IGF1R signaling is an important cascade in Alzheimer's disease (AD); however, its regulation and roles are poorly understood. Due to the presence of β-arrestin and GPCR Receptor Kinase binding sites, this protein has been termed a 'functional hybrid', as it can take part in both kinase and GPCR signaling pathways, further adding to its complexity. The objective of this study is to understand the underlying ncRNA regulation controlling IGF1R and GPCRs in AD to find commonalities in the network. We found through data mining that 45 GPCRs were reportedly deregulated in AD and built clusters based on GO/KEGG pathways to show shared functionality with IGF1R. Eight miRs were further discovered that could coregulate IGF1R and GPCRs. We validated their expression in an AD cell model and probed for common lncRNAs downstream that could regulate these miRs. Seven such candidates were identified and further validated. A combined network comprising IGF1R with nine GPCRs, eight miRs, and seven lncRNAs was created to visualize the interconnectivity within pathways. Betweenness centrality analysis showed a cluster of NEAT1, hsa-miR-15a-5p, hsa-miR-16-5p, and IGF1R to be crucial form a competitive endogenous RNA-based (ceRNA) tetrad that could relay information within the network, which was further validated by cell-based studies. NEAT1 emerged as a master regulator that could alter the levels of IGF1R and associated GPCRs. This combined bioinformatics and experimental study for the first time explored the regulation of IGF1R through ncRNAs from the perspective of neurodegeneration.

Longevity factor FOXO3a: A potential therapeutic target for age-related ocular diseases

The forkhead box protein O3 (FOXO3a) belongs to the subgroup O of the forkhead transcription factor family and plays an important role in regulating the aging process by participating in the regulation of various life processes, including cell cycle arrest, apoptosis, autophagy, oxidative stress, and DNA repair. The eye is an organ that is affected by aging earlier. However, the functional role and potential clinical applications of FOXO3a in age-related eye diseases have not received widespread attention and lacked comprehensive and clear clarification. In this review, we demonstrated the relationship between FOXO3a and visual system health, summarized the functional roles of FOXO3a in various eye diseases, and potential ocular-related therapies and drugs targeting FOXO3a in visual system diseases through a review and summary of relevant literature. This review indicates that FOXO3a is an important factor in maintaining the normal function of various tissues in the eye, and is closely related to the occurrence and development of ophthalmic-related diseases. Based on its vital role in the normal function of the visual system, FOXO3a has potential clinical application value in related ophthalmic diseases. At present, multiple molecules and drugs targeting FOXO3a have been reported to have the potential for the treatment of related ophthalmic diseases, but further clinical trials are needed. In conclusion, this review can facilitate us to grasp the role of FOXO3a in the visual system and provide new views and bases for the treatment strategy research of age-related eye diseases.