'Messy' Processing of χ-conotoxin MrIA Generates Homologues with Reduced hNET Potency.

Integrated venomics techniques have shown that variable processing of conotoxins from Conus marmoreus resulted in a dramatic expansion in the number of expressed conotoxins. One conotoxin from C. marmoreus, the χ-conotoxin MrIA, is a selective inhibitor of human norepinephrine transporters (hNET) and therefore a drug candidate for attenuating chronic neuropathic pain. It has been found that "messy" processing of the MrIA transcripts results in the expression of MrIA analogs with different truncations of the pro-peptide that contains portions of the MrIA molecule. The aim of this study was to investigate if variable processing of the expressed peptides results in modulation of the existing hNET pharmacology or creates new pharmacologies. To this end, a number of MrIA analogs found in C. marmoreus venom were synthesized and evaluated for their activity at hNET receptors. While several of the analogs exhibited norepinephrine transporter inhibitory activity comparable to that of MrIA, none significantly improved on the potency of conotoxin MrIA, and those analogs with disrupted pharmacophores produced greatly reduced NET inhibition, confirming previous structure-activity relationships seen on χ-class conopeptides. Additionally, analogs were screened for new activities on ion channels using calcium influx assays, although no major new pharmacology was revealed.

Inhibition of the norepinephrine transporter by χ-conotoxin dendrimers.

Peptide dendrimers are a novel class of macromolecules of emerging interest with the potential of delayed renal clearance due to their molecular size and enhanced activity due to the multivalency effect. In this work, an active analogue of the disulfide-rich χ-conotoxin χ-MrIA (χ-MrIA), a norepinephrine reuptake (norepinephrine transporter) inhibitor, was grafted onto a polylysine dendron. Dendron decoration was achieved by employing copper-catalyzed alkyne-azide cycloaddition with azido-PEG chain-modified χ-MrIA analogues, leading to homogenous 4-mer and 8-mer χ-MrIA dendrimers with molecular weights ranging from 8 to 22 kDa. These dendrimers were investigated for their impact on peptide secondary structure, in vitro functional activity, and potential anti-allodynia in vivo. NMR studies showed that the χ-MrIA tertiary structure was maintained in the χ-MrIA dendrimers. In a functional norepinephrine transporter reuptake assay, χ-MrIA dendrimers showed slightly increased potency relative to the azido-PEGylated χ-MrIA analogues with similar potency to the parent peptide. In contrast to χ-MrIA, no anti-allodynic action was observed when the χ-MrIA dendrimers were administered intrathecally in a rat model of neuropathic pain, suggesting that the larger dendrimer structures are unable to diffuse through the spinal column tissue and reach the norepinephrine transporter. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Suicidal Attempt among Psychiatry Patients Presented to the Department of Emergency of a Tertiary Care Centre: A Descriptive Cross-sectional Study.

Introduction: More than 700, 000 people die due to suicide every year. Suicide is the fourth leading cause of death among 15-29 year-olds. A total of 77% of global suicides occur in low- and middle-income countries. There is an increasing number of suicide all over the world. There is limited data regarding this issue. The available data are based on police reports or on specific populations. The aim of this study was to find out the prevalence of suicidal attempts among psychiatry patients presented to the Department of Emergency of a tertiary care centre. Methods: A Descriptive cross-sectional study was done in a tertiary care centre from January 2019 to July 2020 after taking Ethical approval from the same institute. Beck Suicide Intent Scale, MINI-7, IPDE and PLESS were used to assess suicidal intent, psychiatric comorbidities, personality disorder and life stress event scores respectively. Bronfenbrenner's Social Ecological Model was used to access various stressors. Point estimate and 95% Confidence Interval were calculated. Results: The Prevalence of suicidal attempts among psychiatry patients in the emergency department was 265 (24.50%), (21.66-26.74, 95% Confidence Interval). The majority were females 135 (51%). The majority attempted at home 238 (89.81%). Poisoning was the most common mode of attempting suicide. Conclusions: The Prevalence of suicidal attempts among psychiatry patients was higher than in the other studies done in similar settings. Keywords: comorbidity; cross-sectional studies; prevalence; psychosocial factors; suicide attempt.

Women's experiences and perception of symptomatic pelvis organ prolapse: A Cross sectional study from Uttarakhand, India.

BACKGROUND: Pelvic Organ Prolapse (POP) negatively affects the health of a woman in terms of physical, social and emotional wellbeing. OBJECTIVE: The aim of this study was to elucidate the experience of living with prolapse and its impact on daily life. METHODS: Women undergoing surgery for pelvic organ prolapse were interviewed to evaluate their sociodemographic profile with subsequent impact on their daily life. RESULTS: Among the 45 cases with POP, 80% belonged to rural areas. Mean age of study group was 53.68 years. Young age at marriage (mean age 17.31), early first child birth (mean age being 20.5 years) and increased parity (86.66% had parity 3 and above) with majority of children born at home under supervision of untrained dais (77.78%) could probably attribute to their prolapse. Approximately 51% thought that prolapse occurs as a result of hard manual work and 64% cases considered it non treatable. POP was associated with poor quality of life in terms of physical, social and sexual life. Decreased sexual frequency was seen in 86.67% cases. 50% cases reported bladder problems. Sense of incomplete evacuation was seen in nearly 35% and constipation was reported by 37%. CONCLUSION: Though there exists a social stigma associated with pelvic organ prolapse, this study showed that in majority, it was the woman herself who delayed medical help. Health care providers should take initiative in educating women regarding prolapse and to make them aware that it is a treatable condition which can improve their quality of life.

Structure-Function of the High Affinity Substrate Binding Site (S1) of Human Norepinephrine Transporter.

The human norepinephrine transporter (hNET) is a member of the neurotransmitter/sodium symporter family, which also includes the neuronal monoamine transporters for serotonin (SERT) and dopamine (DAT). Its involvement in chronic pain and many neurological disorders underlies its pharmaceutical importance. Using the X-ray crystal structures of the human serotonin transporter (hSERT) (PDB 5I6X) and Drosophila melanogaster dopamine transporter (dDAT) (PDB 4M48 and PDB 4XPA) as templates, we developed molecular models for norepinephrine (NE) bound to its high affinity binding site (S1) in the hNET. Our model suggests that the S1 site for NE is deeply buried between transmembrane helices (TMHs) 1, 3, 6, and 8 and overlaps the binding site for leucine in the bacterial leucine transporter (LeuT) and dopamine (DA) in dDAT. Mutational studies identified the functional binding pocket for NE comprised residues A73, A77, N78, V148, N153, I156, G320, F329, N350, S420, G423, and M424, which all influenced NE affinity and/or transport. These effects support a NE-hNET docking model where A73, A77, G320, S420, G423, and M424 form H-bond interactions with NE, V148, I156, and F329 form hydrophobic interactions with NE, whereas N78 affects NE transport and N350 affects NE affinity and transport via an influence on the octahedral co-ordination of the Na1 + ion. Consistent with a conserved structure-function amongst sodium-dependent neurotransmitter transporters, S1 residues A73, A77 (G100 in hSERT), N78, V148 (I150 in hSERT), N153, G320, F329 (Y331 in d DAT), N350, and G423 are conserved in DAT and SERT, indicating they likely play conserved functional roles.