Biology subjects

Sharma, B.

Publications and source records attributed to Sharma, B..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Modulation of microRNA-502-3p significantly influences synaptic activity, dendritic spine density and mitochondrial morphology in the mice brain

Synapse dysfunction is the root cause of Alzheimers disease (AD). Uninterrupted and regulated synapse action is crucial to maintain healthy brain function. Our previous study discovered microRNA-502-3p (miR-502-3p), a synapse-specific miRNA, highly expressed at the AD synapses. Further, in vitro studies unveiled the biological relevance of miR-502-3p in modulating GABA receptor function, synaptic activity and mitochondrial morphology. Current study focuses to investigate the role of miR-502-3p in vivo using stereotaxic injection of miR-502-3p overexpression (OE) and suppression (sponge) lentivirus (LV) into the hippocampus of C57BL/6 wild-type (WT) mice. MiR-502-3p OE and sponge LV were characterized by transducing HT22 cells followed by QRT-PCR and miRNAScope analysis of miR-502-3p. MiR-502-3p OE LV showed a very high-fold upregulation and sponge LV showed significant reduction in miR-502-3p levels. MiR-502-3p OE and sponge LV were injected into three months old WT mice brain hippocampus. Overexpression and suppression effects of miR-502-3p were studied on synaptic proteins, synapse number, mitochondrial morphology and dendritic spine density at eight-weeks post-injection. Mice injected with miR-502-3p OE LV showed reduced levels of synaptic proteins, diminished synapse formation, defective mitochondrial morphology and reduced dendritic spine density relative to control LV treated mice. While mice treated with sponge LV showed elevated levels of synaptic proteins, augmented synapses, improved mitochondrial morphology and elongated dendrites and spine density. Our in vivo study unveiled translational abilities of miR-502-3p to restore synapse dysfunction in AD and other neurological disorders.

neuroscience↗

bioRxiv2025

CDK12/13 inhibition disrupts nucleolar morphology and promotes aberrant expression of IGS transcripts

The transcription-associated cyclin dependent kinases (CDKs) 12 and 13 play important roles in the expression of RNAs involved in DNA damage repair and ribosomal proteins, yet their roles if any, in the regulation of ribosomal DNA expression are unclear. Here we show that these CDKs play critical roles in the processing and degradation of noncoding RNAs in the nucleolus and that inhibition of their function leads to the upregulation of unprocessed ribosomal RNA (rRNA) transcripts in the intergenic spacer (IGS) regions between ribosomal subunits. These upregulated RNAs are aberrantly polyadenylated by the TRAMP complex polymerase TENT4, and are represented as polyadenylated rings surrounding the nucleolus. The accumulation of these noncoding RNAs is associated with increased RNA polymerase II (Pol II)-mediated transcription coupled with failure of degradation by the MTREX (SKIV2L2) RNA helicase, a member of the RNA exosome complex whose expression is prematurely terminated by CDK12/13 inhibition. Altogether, these findings provide new insights into Pol II-mediated transcriptional regulation by CDK12/13 within the nucleolus.

cancer biology↗

bioRxiv2025

Pan-cancer spatial characterization of key immune biomarkers in the tumor microenvironment

Deciphering the composition and spatial organization of the tumor immune microenvironment (TiME) is key to uncovering the mechanisms driving cancer progression and treatment response. Spatial biology techniques like multiplex immunofluorescence (mIF) offer detailed insights into the TiME but are often limited to retrospective research studies of individual cancer types. Conversely, bulk omics techniques have been studied in pan-cancer settings but fail to capture single-cell spatial information. Here, we provide a pan-cancer spatial characterization of key biomarkers (CD8, FOXP3, PD-1, PD-L1) of the TiME using data from a mIF assay performed prospectively in a clinical setting on 2,019 tumors across 14 major cancer types. By integrating interpretable compositional and spatial metrics, we identified patterns of TiME variation that are conserved across cancer types and stages. We assess associations between these TiME spatial factors and tumor, genomic, and clinical features, where the results both extend prior findings and uncover new links. Altogether, our findings offer pan-cancer insights of the TiME to further the fields of spatial biology and cancer immunology.

cancer biology↗

bioRxiv2025

Integrated Multi-Omics Analyses of Synaptosomes Revealed Synapse-Centered Novel Targets in Alzheimer's Disease

AO_SCPLOWBSTRACTC_SCPLOWSynapse dysfunction is an early event in Alzheimers disease (AD) caused by various factors such as Amyloid beta, p-tau, inflammation, and aging. However, the exact molecular mechanism of synapse dysfunction in AD is largely unknown. To understand this, we comprehensively analyzed the synaptosome fraction in postmortem brain samples from AD patients and cognitively normal individuals. We conducted high-throughput transcriptomic analyses to identify changes in microRNA (miRNA) and mRNA levels in synaptosomes extracted from the brains of both unaffected individuals and those with Alzheimers disease (AD). Additionally, we performed mass spectrometry analysis of synaptosomal proteins in the same sample group. These analyses revealed significant differences in the levels of miRNAs, mRNAs, and proteins between the groups. To further understand the pathways or molecules involved, we used an integrated omics approach and studied the molecular interactions of deregulated synapse miRNAs, mRNAs, and proteins in the samples from individuals with AD and the control group, which demonstrated the impact of deregulated miRNAs on their target mRNAs and proteins. Furthermore, the DIABLO analysis highlighted complex relationships between mRNAs, miRNAs, and proteins that could be key in understanding the pathophysiology of AD. Our study identified synapse-centered novel candidates that could be critical in restoring synapse dysfunction in AD.

neuroscience↗

bioRxiv2025

MiRNA-501-3p and MiRNA-502-3p: A Promising Biomarker Panel for Alzheimer's Disease

INTRODUCTIONAlzheimers disease (AD) lacks a less invasive and early detectable biomarker. Here, we investigated the biomarker potential of miR-501-3p and miR-502-3p using different AD sources. METHODSMiR-501-3p and miR-502-3p expressions were evaluated in AD CSF exosomes, serum exosomes, familial and sporadic AD fibroblasts and B-lymphocytes by qRT-PCR analysis. Further, miR-501-3p and miR-502-3p expressions were analyzed in APP, Tau cells and media exosomes. RESULTSMiR-501-3p and miR-502-3p expressions were significantly upregulated in AD CSF exosomes relative to controls. MiRNA levels were high in accordance with amyloid plaque and NFT density in multiple brain regions. Similarly, both miRNAs were elevated in AD and MCI serum exosomes compared to controls. MiR-502-3p expression was high in fAD and sAD B-lymphocytes. Finally, miR-501-3p and miR-502-3p expression were elevated intracellularly and secreted extracellularly in response to APP and Tau pathology. DISCUSSIONThese results suggest that miR-501-3p and miR-502-3p could be promising biomarkers for AD.

neuroscience↗

bioRxiv2025

MicroRNA-502-3p modulates the GABA A subunits, synaptic proteins and mitochondrial morphology in hippocampal neurons

MicroRNA-502-3p (MiR-502-3p), a synapse enriched miRNA is considerably implicated in Alzheimers disease (AD). Our previous study found the high expression level of miR-502-3p in AD synapses relative to controls. Further, miR-502-3p was found to modulate the GABAergic synapse function via modulating the GABA A receptor subunit -1 (GABRA1) protein. The current study is attempted to examine the impact of miR-502-3p on other GABA subunit proteins, synaptic proteins, mitochondrial morphology and other hippocampal neuron genes. Mouse hippocampal neuronal (HT22) cells were transfected with miR-502-3p overexpression (OE) vector, miR-502-3p sponge (suppression) vector and scramble control vector. MiR-502-3p vectors transfection was confirmed by fluorescence microscopy. MiR-502-3p expression and GABRA1 expression was confirmed by qRT-PCR and miRNAScope in-situ hybridization. GABA A subunit and synaptic proteins were studied by immunoblotting analysis and mitochondrial morphology was analyzed by transmission electron microscopy (TEM) analysis. Further, Affymetrix gene array analysis was conducted in miR-502-3p overexpressed and suppressed cells. Our results observed that elevated miR-502-3p, negatively modulates the GABRA1 level. The levels of GABA A subunit and synaptic proteins were reduced by ectopic expression of miR-502-3p and increase by miR-502-3p suppression. The mitochondrial morphology was found to be improved in-terms of their number and length in miR-502-3p suppressed cells. Further, Gene array analysis unveiled the deregulation of several genes by miR-502-3p, which are associated with oxidative stress, immune response and synaptic function. These results provide new insights and an update to understand the biological roles of miR-502-3p in regulation of neuron function and synaptic activity.

neuroscience↗

bioRxiv2025

Acoustic features of and behavioral responses to emotionally intense mouse vocalizations

Social vocalizations contain cues that reflect the motivational state of vocalizing animals. Once perceived, these cues affect the internal state and behavioral responses of listening animals. Using CBA/CAJ mice, this study examined acoustic cues that signal intensity in male-female interactions, then compared behavioral responses to intense mating vocal sequences with those from another intense behavioral context, restraint. Experiment I examined behaviors and vocalizations associated with male-female social interactions. Based on several behaviors, we distinguished more general, courtship-type interactions from mating interactions involving mounting or attempted mounting behaviors. We then compared vocalizations between courtship and mating. The increase in behavioral intensity from courtship to mating was associated with altered syllable composition, more harmonic structure, lower minimum frequency, longer duration, reduced inter-syllable interval, and increased sound intensity. Based on these features, we constructed highly salient playback stimuli associated with mating. In Experiment II, we compared behavioral responses to playback of these mating sequences with responses to playback of aversive vocal sequences produced by restrained mice. Subjects were males and estrus females. We observed a range of behavioral responses. Some (e.g., Attending and Stretch-Attend) showed similar responses across playback type and sex, while others were context dependent (e.g., Flinching, Locomotion). Still other behaviors showed either an effect of sex (e.g., Self-Grooming, Still-and-Alert) or an interaction between playback type and sex (Escape). These results demonstrate both state-dependent features of mouse vocalizations and their effectiveness in evoking a range of behavioral responses, independent of contextual cues provided by other sensory stimuli or behavioral interactions.

neuroscience↗

bioRxiv2024

Mgat4b mediated selective N-glycosylation regulates melanocyte development and melanoma progression

Melanocyte development involves key pathways that are often recapitulated during melanoma initiation, highlighting the importance of understanding the regulators that control these early processes and also contribute to cancer onset. Our study identifies mgat4b, a glycosyl transferase involved in selective N-glycan branching enriched in pigment progenitors, as a key regulator of directional melanocyte migration and establishment of melanocyte stem cell (McSC) pool during early development. Single cell RNA (scRNA) sequencing analysis in zebrafish upon targeted disruption of mgat4b reveals, that migratory melanocyte progenitors marked by galectin expression fail to persist. Lectin affinity proteomic analysis reveals the glycosylation of key melanocyte proteins GPNMB, KIT, and TYRP1 to be under the control of MGAT4B in melanocytic cells. Additionally, mislocalization of Junctional plakoglobin (JUP) explains the observed defects in cell adhesion and migration to be regulated by MGAT4B but not its isozyme MGAT4A. Our meta-analysis further reveals that melanoma patients with both the BRAFV600E mutation and elevated MGAT4B levels have significantly worse survival outcomes compared to those with only the BRAFV600E mutation. By leveraging the MAZERATI platform to model BRAFV600E driver mutation in vivo, we show that mgat4b mutant cells fail to aggregate and initiate tumors. RNA profiling of the transformed melanocytes revealed cell-cell junction, adhesion and ECM binding to be probable contributing factors that resulted in the failure of tumor onset. Using a small-molecule inhibitor we demonstrate the inhibitory role of this complex N-glycosylation in the progression of early-stage melanoma. Our study underscores the importance of selective N-glycan branching in both melanocyte development and melanoma initiation, suggesting MGAT4B as a promising therapeutic target for melanoma treatment.

cancer biology↗

bioRxiv2024

MHC class I / II restricted T cell epitopes from clinical isolate of Mycobacterium tuberculosis: A potential candidate for vaccine development for Tuberculosis

Tuberculosis is major challenge to the health care system with TB associated death rates increasing annually. Optimum management of TB (particularly latent or MDR cases) warrants use of immunological approaches like subunit or peptide-based vaccination for tailoring effector immunity in patients. Since MHC class I is a potent enhancer element of host immunity and effective in clearing large variety of intracellular pathogens or tumors. In this context, we explore whether MHC-I restricted peptides from clinical isolates of M. tuberculosis can be used as an adjuvant for augmenting host immune responses. In the present study, we have synthesized various peptides from clinical isolates of M. tuberculosis which were having high affinity for Class I MHC molecules as potential immune enhancer for T cell or iNKT cell populations. We have evaluated the immunogenic potential of various MHC class I restricted epitopes (Rv2588c, Rv1357, Rv0148, Rv2973, Rv2557 and Rv2445) which were derived from clinical isolates of M. tuberculosis on increased proliferation of T or iNKT cells, release of IFN gamma secreted by T cells as well as NO as indicative parameters of immuno-stimulation. As expected, FACS and ELISA data clearly revealed that these peptides were potentially immunogenic for PBMCs from both healthy as well as 10 HC PTB patients. Our data clearly demonstrated a significant immune response in the PBMC from w PTB patients over healthy individuals which mimicked booster response. Our cytokine and nitric oxide data further revealed the influence of these peptides on sensitizing innate immune response as well. SignificanceOur study demonstrates the significance of MHC class I restricted peptides from M. tuberculosis for inducing potential immunogenic responses in host that may qualify them as potent vaccine candidate. To the best of our knowledge this is the first immune monitoring protocol describing the impact of synthetic novel MHC class I restricted T-cell epitope (Rv2588c, Rv0148) on cell mediated and innate immune response in PBMC populations and suggests their potential as vaccine candidate

immunology↗

bioRxiv2024

Increased burden of rare risk variants across gene expression networks predisposes to sporadic Parkinson's disease

Alpha-synuclein (Syn) is an intrinsically disordered protein that accumulates in the brains of patients with Parkinsons disease and forms intraneuronal inclusions called Lewy Bodies. While the mechanism underlying the dysregulation of Syn in Parkinsons disease is unclear, it is thought that prionoid cell-to-cell propagation of Syn has an important role. Through a high throughput screen, we recently identified 38 genes whose knock down modulates Syn propagation. Follow up experiments were undertaken for two of those genes, TAX1BP1 and ADAMTS19, to study the mechanism with which they regulate Syn homeostasis. We used a recently developed M17D neuroblastoma cell line expressing triple mutant (E35K+E46K+E61K) "3K" Syn under doxycycline induction. 3K Syn spontaneously forms inclusions that show ultrastructural similarities to Lewy Bodies. Experiments using that cell line showed that TAX1BP1 and ADAMTS19 regulate how Syn interacts with lipids and phase separates into inclusions, respectively, adding to the growing body of evidence implicating those processes in Parkinsons disease. Through RNA sequencing, we identified several genes that are differentially expressed after knock-down of TAX1BP1 or ADAMTS19. Burden analysis revealed that those differentially expressed genes (DEGs) carry an increased frequency of rare risk variants in Parkinsons disease patients versus healthy controls, an effect that was independently replicated across two separate cohorts (GP2 and AMP-PD). Weighted gene co-expression network analysis (WGCNA) showed that the DEGs cluster within modules in regions of the brain that develop high degrees of Syn pathology (basal ganglia, cortex). We propose a novel model for the genetic architecture of sporadic Parkinsons disease: increased burden of risk variants across genetic networks dysregulates pathways underlying Syn homeostasis, thereby leading to pathology and neurodegeneration.

cell biology↗

bioRxiv2024

Closed-loop modulation of remote hippocampal representations with neurofeedback

Humans can remember specific remote events without acting on them and influence which memories are retrieved based on internal goals. However, animal models typically present sensory cues to trigger memory retrieval and then assess retrieval based on action. Thus, it is difficult to determine whether measured neural activity patterns relate to the cue(s), the memory, or the behavior. We therefore asked whether retrieval-related neural activity could be generated in animals without cues or a behavioral report. We focused on hippocampal "place cells" which primarily represent the animals current location (local representations) but can also represent locations away from the animal (remote representations). We developed a neurofeedback system to reward expression of remote representations and found that rats could learn to generate specific spatial representations that often jumped directly to the experimenter-defined target location. Thus, animals can deliberately engage remote representations, enabling direct study of retrieval-related activity in the brain.

neuroscience↗

bioRxiv2024

The MYCN 5' UTR as a therapeutic target in neuroblastoma

Tumor cell amplification of the MYCN transcription factor is seen in half of patients with high-risk neuroblastoma, where it functions as an oncogenic driver associated with metastatic disease and poor survival. Yet, direct targeting of MYCN has been met with little success, prompting efforts to inhibit its expression at multiple levels. MYCN-amplified neuroblastoma cells have an increased requirement for protein synthesis to meet the overwhelming transcriptional burden imposed by oncogenic MYCN. Here, we take advantage of this vulnerability to interrogate the therapeutic potential of inhibiting the activity of the eukaryotic translation initiation factor 4A1 (eIF4A1), an RNA-helicase responsible for resolving structural barriers such as polypurine preponderance within 5' untranslated regions (UTRs). We observed that eIF4A1 is a key regulator of transcript-specific mRNA recruitment in MYCN-overexpressing neuroblastomas and MYCN-associated transcripts rank highly in polypurine-rich 5' UTR sequences, the majority of which have critical roles in cell proliferation. Using CMLD012824, a novel synthetic amidino-rocaglate (ADR) derivative, we demonstrate selectively increased eIF4A1 affinity for polypurine-rich 5' UTRs, including the MYCN mRNA, leading to translation inhibition and cytotoxicity in human neuroblastoma cell lines and animal models. Through ribosome profiling and PAR-CLIP analysis, we show that ADR-mediated clamping of eIF4A1 onto mRNA spans the full lengths of target transcripts, whereas translational inhibition is mediated selectively through 5' UTR binding. Both cap-dependent and cap-independent translation of MYCN are disrupted, pointing to the ability of CMLD012824 to disrupt non-canonical translation initiation. Our studies provide insights into the functional role of eIF4A1 in meeting the increased protein synthesis demands of MYCN-amplified neuroblastoma and suggest that its disruption may be therapeutically beneficial in this disease.

cancer biology↗

bioRxiv2023

Hypoxia regulate developmental coronary angiogenesis potentially through VEGFR2- and SOX17-mediated signaling

BackgroundCoronary vessels in embryonic mouse heart arises from multiple progenitor population including sinus venosus (SV), endocardium, and proepicardium. ELA/APJ signaling is shown to regulate coronary growth from SV pathway within the subepicardium, whereas VEGF-A/VEGF-R2 pathways is implicated to regulate coronary growth from endocardium pathway. Our previous study show hypoxia as a potential signaling cue to stimulate overall coronary growth and expansion within the myocardium. However, the role of hypoxia and its downstream signaling pathways in the regulation of coronary vessel development is not known. In this study, we investigated the role of hypoxia in coronary vessel development and have identified SOX17- and VEGF-R2-mediated signaling as a potential downstream pathway of hypoxia in the regulation of coronary vessel development. ResultsWe show that hypoxia gain-of-function in the myocardium through upregulation of HIF-1 disrupts the normal pattern of coronary angiogenesis in developing mouse hearts and displays phenotype that is reminiscent of accelerated coronary growth. We show that VEGF-R2 expression is increased in coronary endothelial cells under hypoxia gain-of-function in vivo and in vitro. Furthermore, we show that SOX17 expression is upregulated in developing mouse heart under hypoxia gain-of-function conditions, whereas SOX17 expression is repressed under hypoxia loss-of-function conditions. Furthermore, our results show that SOX17 loss-of-function disrupts normal pattern of coronary growth. ConclusionCollectively, our data provide strong phenotypic evidence to show that hypoxia might regulate coronary growth in the developing mouse heart potentially through VEGF-R2- and SOX17-mediated downstream signaling pathways.

developmental biology↗

bioRxiv2023

Antibody targeting of aging damaged isoDGR-protein doubles lifespan in a mouse model of chronic inflammation

Aging is the result of the accumulation of molecular damages that impair normal biochemical activities. We previously reported that aging-damaged amino acid sequence NGR (Asn-Gly-Arg) results in a gain-of-function conformational switching to isoDGR (isoAsp-Gly-Arg) motif. This integrin-binding motif activates leukocytes to induce chronic inflammation, which are characteristic features of age-linked cardiovascular disorders. We now report that anti-isoDGR immunotherapy doubles lifespan in mouse model of chronic inflammation. We observed extensive accumulation of isoDGR and inflammatory cytokine expression in multiple tissues from Pcmt1-KO and old WT animals, which could also be induced via injection of isoDGR-modified plasma proteins or synthetic peptides into young WT animals. However, weekly injection of anti-isoDGR mAb (1mg/kg) was sufficient to significantly reduce isoDGR-modified proteins and pro-inflammatory cytokine expression, improve behaviour and coordination, and double the average lifespan of Pcmt1-KO mice. Mechanistically, isoDGR-mAb mediated the immune clearance of damaged isoDGR-proteins by antibody-dependent cellular phagocytosis. These results indicate that immunotherapy targeting aging-damaged proteins may represent effective interventions for a range of age-linked degenerative disorders. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=105 SRC="FIGDIR/small/532237v1_ufig1.gif" ALT="Figure 1"> View larger version (12K): org.highwire.dtl.DTLVardef@81610borg.highwire.dtl.DTLVardef@a22aaorg.highwire.dtl.DTLVardef@169fe50org.highwire.dtl.DTLVardef@1b73d11_HPS_FORMAT_FIGEXP M_FIG Anti-isoDGR immunotherapy induces immune clearance of aging damaged isoDGR-proteins to reduce chronic inflammation, improve behaviour and coordination, and double lifespan in PCMT-/- mice. C_FIG

biochemistry↗

bioRxiv2023

Migration and establishment of progenitor pool of melanocytes is governed by SEMA3E-PLXND1 signaling

Vertebrate pigmentation is an outcome of an interplay of several signaling pathways that result in immense diversity of pigment patterns observed across the animal kingdom. Transitory nature of these signaling events impedes deciphering pathways that control migration and establishment of melanocyte stem cells (McSC), necessary for pigment patterning. Using zebrafish and cultured mammalian melanocytes, we uncover a hitherto unknown role for Plexin D1 signaling. This pathway directs migration by F-actin modulation and further dictates subsequent functional states of melanocytes through a transcriptional response. In zebrafish, abrogation of PLXND1 derails melanocyte migration and reduces mid-line melanophores emerging from the regeneration competent McSC pool. In cultured melanocytes, activation of PLXND1 by the ligand semaphorin 3E reduces the velocity of migration, influences directional correlation, and promotes movement towards positive cues such as SCF. PLXND1 activation results in EGFR signaling necessary for McSC establishment, and induces GNAS, an effector of MC1R pathway involved in melanocyte maturation. Identification of this long-range secreted negative chemotactic signaling provides a missing player and enriches reaction diffusion model for pigment patterning.

developmental biology↗

bioRxiv2023

Spatially aware deep learning reveals tumor heterogeneity patterns that encode distinct kidney cancer states

Background Abstract Background Results Discussion Methods Data Availability Code Availability Author Contributions Competing Interests Extended Data References Renal cell carcinoma (RCC) is among the 10 most common cancers worldwide and is comprised of several histological subtypes1. The clear cell histological subtype (ccRCC) is the most common form of RCC and accounts for the vast majority (75-80%) of metastatic cases1. In addition to highly recurrent mutations in hypoxia (VHL) and chromatin regulator genes (e.g. PBRM1, BAP1, SETD2), ccRCC exhibits extensive genomic intratumoral heterogeneity (ITH)2, which wa ...

cancer biology↗

bioRxiv2022

Effect of 15 days hindlimb unloading on baroreflex sensitivity, Hear rate variability and Carotid artery structure in rats

IntroductionIn space, cephalad shift of body fluid equalizes the blood pressure throughout the body leading to various cardiovascular disturbances in space and upon return on earth. Effects of microgravity on humans can be simulated on earth by hindlimb unloading (HU) rat models l. This study was planned to examine the Effect of 15 days hindlimb unloading on baroreflex sensitivity, Herat rate variability (HRV) and carotid artery structure in rats. Material and methods18 male Wistar rats weighing 250-300 gm were randomly divided into control and hindlimb unloading groups and housed in separate cages for 15 days. Body weight, food and water intake was measured every day. The pelvic suspension method was used to simulate effects of microgravity. To record HRV, ECG was recorded in lead II configuration on the 15th day. Then blood pressure was recorded directly from the carotid artery. Linear regression of arterial pressure and RR interval used to derive the Baroreflex sensitivity. Vessel wall thickness, intimal thickness, smooth muscle cell layer thickness & luminal diameter were compared after H&E staining. Ultrathin sectioning and counter-staining was done for electron microscopy and Changes in endothelial thickness, elastic lamina, and deeper artery structures were observed. Statistical analysis was done using Graphpad Prism (version 9.0). Unpaired t-test, Mann Whitney and 2 way ANOVA were used according to groups and distribution of parameters. ResultsWe found significant differences in Food intake (p {square}0.001), Body weight (p {square}0.001), Heart rate (p=0.031), BRS (p= 0.026), R-R interval (p=0.0246), heart rate variability parameters {SDSD (p=0.0001), RMSD (p= 0.0001), VLF(p=0.001),HF (p=0.0054), LF/HF Ratio (p= 0.0001)}. We did not found significant changes in Water intake, MAP, SBP, DBP, Vessel wall thickness, Luminal Diameter, Intimal thickness, Smooth muscle thickness, in H&E staining and in electron microscopy. ConclusionChronic microgravity simulation using pelvic suspension showed a decrease in BRS after 15 days of HU; however 15 days of HU was not insufficient to produce any structural changes in the carotid artery. BRS changes were accompanied by change in vascular vasoconstriction and vasodilation properties which were due to alteration in the sympathetic and parasympathetic outflow.

physiology↗

bioRxiv2022

Emotional Vocalizations Alter Behaviors and Neurochemical Release into the Amygdala

The basolateral amygdala (BLA), a brain center of emotional expression, contributes to acoustic communication by first interpreting the meaning of social sounds in the context of the listeners internal state, then organizing the appropriate behavioral responses. We propose that modulatory neurochemicals such as acetylcholine (ACh) and dopamine (DA) provide internal-state signals to the BLA while an animal listens to social vocalizations. We tested this in a vocal playback experiment utilizing highly affective vocal sequences associated with either mating or restraint, then sampled and analyzed fluids within the BLA for a broad range of neurochemicals and observed behavioral responses of adult male and female mice. In male mice, playback of restraint vocalizations increased ACh release and usually decreased DA release, while playback of mating sequences evoked the opposite neurochemical release patterns. In non-estrus female mice, patterns of ACh and DA release with mating playback were similar to males. Estrus females, however, showed increased ACh, associated with vigilance, as well as increased DA, associated with reward-seeking. Experimental groups that showed increased ACh release also showed the largest increases in an aversive behavior. These neurochemical release patterns and several behavioral responses depended on a single prior experience with the mating and restraint behaviors. Our results support a model in which ACh and DA provide contextual information to sound analyzing BLA neurons that modulate their output to downstream brain regions controlling behavioral responses to social vocalizations. SIGNIFICANCE STATEMENTIn social communication by sound, an animal interprets the meaning of vocalizations based on its prior experience, other sensory stimuli, and its internal state. The basolateral amygdala (BLA), a brain center of emotional expression, contributes to this analysis. We found that the modulatory neurochemicals acetylcholine and dopamine were released differentially into the BLA depending on the emotional content of the vocalizations, the sex and hormonal state of the animal, as well as its prior experience. Our results suggest that acetylcholine and dopamine provide context- and hormonal state-dependent information to sound-analyzing BLA neurons that modulates their output to downstream brain centers controlling behavioral responses to social vocalizations.

neuroscience↗