Biology subjects

Neupane, N.

Publications and source records attributed to Neupane, N..

6 recordsLinked to original sources

bioRxiv2026

Large-scale atmospheric circulation cells regulate migratory dynamics of the iconic monarch butterfly

Understanding the impacts of climate on migratory dynamics is a priority for global change research, especially as phenological mismatches have been identified as a primary concern for long-distance migration. The eastern monarch (Danaus plexippus) is a flagship species for insect migration, but there has been surprisingly little research on their spring and summer migratory timing and mismatches with their key breeding resources. We show that spring, but not summer, phenological mismatch with their milkweed host plants has the potential to be a limiting factor in the eastern monarchs yearly population growth. To better understand arrival at their breeding grounds, we developed models specifically to tease apart the factors that push (from departure grounds), pull (towards arrival grounds), or facilitate flow (in the flight corridor) during migration. We found wind (flow) dynamics to be the most important factor associated with arrival timing, especially in spring. Further, we show how spring and summer migratory flyways coincide with the large-scale Hadley and Ferrel atmospheric cells respectively, and how their dynamics appear to be essential for understanding monarch migratory timing.

ecology↗

bioRxiv2026

Loss of mitochondrial co-chaperone GRPEL2 protects mice from age- and diet-induced obesity

Mitochondrial protein homeostasis intersects with metabolic control, but the in vivo roles of specific mitochondrial co-chaperones remain unclear. The chaperone mtHSP70 plays a key role in import and folding of nuclear-encoded proteins targeted to mitochondrial matrix. Its protein folding cycle is regulated by the GrpE-like nucleotide exchange factor GRPEL1. Vertebrates also have a GRPEL2 paralog, postulated as the stress-sensitive counterpart, but its physiological relevance is not known. We show here that GRPEL2 is not essential for viability in mice, and its absence does not induce proteotoxic stress responses in stark contrast to GRPEL1. However, we find that GRPEL2 has a role in regulating body weight homeostasis. GRPEL2 knockout mice are protected from age- and diet-induced weight gain and maintain a better metabolic health and insulin sensitivity. Transcriptional profiling revealed minimal changes in liver and skeletal muscle, whereas white adipose tissue from Grpel2-deficient mice lacked the obesity-associated remodeling seen in controls. We propose that GRPEL2 fine-tunes metabolic setpoints without broadly perturbing mitochondrial protein import, thereby maintaining adipose tissue health during nutritional excess. These findings show that subtle alterations in mitochondrial chaperone systems reshape systemic metabolism and could suggest strategies to mitigate obesity and insulin resistance through targeted modulation of mitochondrial proteostasis.

physiology↗

bioRxiv2024

The Autonomic Nervous System (ANS)-Immune Network in People Living With HIV

PurposePre-clinical studies have demonstrated direct influences of the autonomic nervous system (ANS) on the immune system. However, it remains unclear if ANS-immune connections delineated in pre-clinical studies underlie the relationship between autonomic dysregulation and chronic inflammatory diseases in patients with HIV. This study had three aims: 1.) Examine the relationship between IL-6 and the parasympathetic/vagal component of baroreflex sensitivity (BRS-V) in people with HIV; 2.) Determine if the subtype and severity of HIV-autonomic neuropathy (AN) would predict distinct immunotypes; 3.) Compare the burden of non-AIDS-related co-morbidities between immunotypes. Methods79 adults with well-controlled HIV underwent a standard battery of autonomic function tests summarized as the Composite Autonomic Severity Score and vagal and adrenergic baroreflex sensitivity (BRS-V and BRS-A).1 Levels of immune biomarkers were measured in all participants using the Target 96 Inflammation Panel on the Olink proteomics platform and immunotypes were identified using unbiased, non-negative matrix factorization. Mass cytometry (CyTOF) was completed on a subset of participants with and without autonomic neuropathy (N = 10). ResultsReduced BRS-V predicted higher levels of IL-6 (p=0.002). A pro-inflammatory immunotype defined by elevations in type 1 cytokines (IL-6, IL-17) and increased numbers of CD8+ T-cells was associated with autonomic neuropathy characterized by deficits in sympathetic nervous system activity (aOR=4.7, p=0.017). This pro-inflammatory immunotype was older with a greater burden of co-morbidities. ConclusionDeficits in the parasympathetic/cardiovagal and the sympathetic nervous system are associated with inflammation and disease burden in people living with HIV. Future longitudinal research is needed to examine causality.

immunology↗

bioRxiv2024

Deep computer vision reveals the mediation of thermal-melanism and body size by precipitation and sex in a threatened alpine butterfly, Parnassius smintheus

Insect morphologies are strongly tied to selective forces, yet due to variation in these forces and finite resources, insects must strategically invest in select morphologies while deprioritizing others. Melanism and body size may be one such potential trade-off that insects navigate and these two factors are important for fecundity, dispersal, thermoregulation, anti-desiccation, and immunity. In this work, we examined how sex and environmental factors mediate a potential body-size/melanism trade-off in the cold-adapted butterfly Parnassius smintheus (Lepidoptera: Papilionidae). We used deep computer vision approaches and museum specimen photography to process over 1,000 images of the species. We found that body-size and melanism are strongly mediated by temperature and elevation (thermal-melanism hypothesis) and that precipitation mediates these slopes for males and females differently. Notably, under the wettest conditions, females exhibit stronger concordance with the thermal-melanism hypothesis while the relationship for males is inverted, suggesting increased competition among males in cold-wet environments. Our results highlight the importance of considering sex when examining how the environment influences intraspecific morphological variation, especially under projected scenarios of global climate change.

ecology↗

bioRxiv2023

Rising minimum temperatures contribute to 50 years of shifting Arctic and boreal butterfly communities in North America

AbstractGlobal climate change has been identified as a major driver of observed insect declines, yet in many regions there are critical knowledge gaps for how communities are responding to climate. Poleward regions are of particular interest because warming is most rapid while biodiversity data are most sparse. Building on recent advances in occupancy modeling of presence-only data, we reconstructed 50 years (1970-2019) of butterfly population trends in response to rising minimum temperatures in one of the most under sampled regions of the continent. Among 90 modeled species, we found that cold-adapted species are far more often in decline compared to their warm-adapted, more southerly distributed counterparts. Further, in a post-hoc analysis using species traits, we find that species range-wide average annual temperature and wingspan are a consistent predictor of occupancy changes. Species with warmer ranges and larger wingspans were most likely to be increasing in occupancy. Our results provide the first look at macroscale butterfly biodiversity shifts in a critically under sampled region of North America. Further, these results highlight the potential of leveraging the wealth of presence only data, the most abundant source of historical insect biodiversity. New approaches to the modeling of presence only data will match recent increases in community science participation with sparse historical records to reconstruct trends even in poorly sampled regions.

ecology↗

bioRxiv2021

A national analysis of trends in COVID-19 infection and clinical management in Veterans Health Administration medical facilities

OBJECTIVEWe explored longitudinal trends in sociodemographic characteristics, reported symptoms, laboratory findings, pharmacological and non-pharmacological treatment, comorbidities, and 30-day in-hospital mortality among hospitalized patients with coronavirus disease 2019 (COVID-19). METHODSThis retrospective cohort study included 43,267 patients diagnosed with COVID-19 in the Veterans Health Administration between 03/01/20 and 08/31/20 and followed until 09/30/20. We focused our analysis on patients that were subsequently hospitalized, and categorized them into groups based on the month of hospitalization. We summarized our findings through descriptive statistics. We used a nonparametric rank-sum test for trend to examine any differences in the distribution of our study variables across the six months. RESULTSDuring our study period, 8,240 patients were hospitalized, and 1,081 (13.1%) died within 30 days of admission. Hospitalizations increased over time, but the proportion of patients that died consistently declined from March (N=221/890, 24.8%) to August (N=111/1,396, 8.0%). Patients hospitalized in March compared to August were younger on average, mostly black, and symptomatic. They also had a higher frequency of baseline comorbidities, including hypertension and diabetes, and were more likely to present with abnormal laboratory findings including low lymphocyte counts and elevated creatinine. Lastly, receipt of mechanical ventilation and Hydroxychloroquine declined from March to August, while treatment with Dexamethasone and Remdesivir increased. CONCLUSIONWe found evidence of declining COVID-19 severity and fatality over time within a national health care system.

scientific communication and education↗