Biology subjects

Wright, D. C.

Publications and source records attributed to Wright, D. C..

7 recordsLinked to original sources

bioRxiv2026

Alpha-linolenic acid and dietary protein minimally but differentially regulate white adipose tissue lipolysis in female mice fed moderate-fat diets

Omega-3 polyunsaturated fatty acids (n-3 PUFA) influence white adipose tissue (WAT) lipid buffering capacity; however, sex-specific regulation remains understudied. We recently reported that male mice fed a diet containing high alpha-linolenic acid (ALA) had increased WAT mass, reduced serum triglycerides and elevated lipolysis compared to mice fed a diet containing recommended levels of ALA, independent of background dietary protein. The current study examined whether subcutaneous and visceral WAT (scWAT, vWAT) lipolytic activity was altered in female C57BL/6N mice (n=16/group) fed low-ALA (1% energy) or high-ALA (3% energy) diets containing skim milk protein (SMP) or soy protein isolate (SPI) for 8 weeks. Body weight, WAT depot weights and serum triglycerides were unchanged in response to ALA content. Lipolytic markers were mostly unchanged by ALA content except for an increase in adipose triglyceride lipase (ATGL) in vWAT, while diets containing SPI modestly reduced serum cholesterol levels and increased total hormone-sensitive lipase (HSL) content in vWAT. Collectively, WAT lipolytic markers in female mice showed minimal response to diets containing high ALA content, unlike that previously reported in male mice. These results highlight the importance of considering both sexes to ensure generalizability of findings when investigating diet regulation of WAT lipid metabolism.

physiology↗

bioRxiv2026

Single cell multiomics reveal clonal and functional dynamics of MDS stem/progenitor cells during hypomethylating therapy

Progressive somatic mutations in hematopoietic stem cells (HSCs) drive the development of myelodysplastic neoplasms (MDS). Hypomethylating agents such as azacitidine (AZA) can improve blood counts and reduce blasts, although responses are rarely durable. Determinants of AZA response are complex and incompletely understood, although accumulating evidence suggests that epigenetic rewiring of mutated HSCs underlies improved hematopoietic output. Using single cell multiomics on longitudinal bone marrow samples, we show that AZA responsiveness involves expansion of cells with transcriptomic profiles shared with hematopoietic stem and progenitor cells (HSPCs) from healthy donors. These regenerating cells are depleted of copy number variations and of TP53 mutations. We also identify patient-restricted cell populations, some of which recede through transcriptional restoration or AZA cytotoxicity, and others which expand, regardless of initial clinical response, and dominate at progression. Individual patients carried multiple patient-restricted populations which had unique surface immunophenotypes and were genetically distinct. Strikingly, sorted cells from in vivo progression clones that were AZA-refractive in patients regained AZA-sensitivity when cultured in vitro, suggesting that lack of AZA response at the cellular level can be modulated by cell-extrinsic factors in vivo. Overall, we find that AZA response involves partial hematopoietic regeneration via functional differentiation of mutated, but not cytogenetically abnormal HSPCs, and that persistence of AZA-refractive sub-populations contributes to eventual disease progression.

cancer biology↗

bioRxiv2025

The fecal microbiota transplantation from drug-naive schizophrenia patients distinctively changes gut microbiome and metabolic profiles in male and female mice

BackgroundEmerging evidence suggests a role for the gut microbiome in schizophrenia (SCZ) and antipsychotic-induced metabolic perturbations. Using human fecal microbiota transplantation (FMT) in mice, this study investigated the role of gut microbiome in metabolic changes related to SCZ and antipsychotic (olanzapine) treatment. Methods5-6 weeks old germ-free NIH Swiss mice of both sexes received microbiota from either SCZ patients (SCZ-FMT) or healthy controls (HC-FMT) followed by a diet with or without olanzapine for six-weeks. Food intake and body weight were monitored weekly, and an intraperitoneal glucose tolerance test and open field test were performed. Serum glucose, and insulin were measured. Gut microbiome characterization and short-chain fatty acids (SCFAs) quantification were performed in the cecal samples using 16S rRNA gene sequencing and gas chromatography-mass spectrometry, respectively. ResultsOlanzapine treatment decreased the locomotor activity in the open field test, irrespective of sex or microbiota. Female SCZ-FMT recipient mice exhibited insulin resistance compared to HC-FMT, irrespective of olanzapine treatment. Female SCZ-FMT mice showed significantly lower alpha-diversity compared to HC-FMT, whereas olanzapine treatment increased alpha-diversity. SCZ-FMT and olanzapine treatment differentially altered the microbial abundances, and metabolic pathways in male and female mice. Interestingly, cecal SCFAs, mainly acetate levels, were significantly decreased in female SCZ-FMT mice compared to HC-FMT, while olanzapine treatment increased acetate levels in male mice. Both male and female SCZ-FMT mice showed elevated levels of isovaleric acid compared to HC-FMT. ConclusionThese preliminary findings suggest that gut microbiome could be a predisposing factor contributing to the intrinsic risk of developing type 2 diabetes associated with SCZ in females. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=80 SRC="FIGDIR/small/675957v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@8cfd10org.highwire.dtl.DTLVardef@3a6031org.highwire.dtl.DTLVardef@813428org.highwire.dtl.DTLVardef@87609e_HPS_FORMAT_FIGEXP M_FIG Graphical abstract C_FIG

neuroscience↗

bioRxiv2025

Protective effects of central leptin on whole-body energy homeostasis upon acute olanzapine exposure

Second-generation antipsychotic use is associated with severe metabolic side effects such as obesity and type 2 diabetes. Leptin is a hormone that is secreted by adipose tissue, and it acts on the brain to decrease body weight by reducing food intake and stimulating energy expenditure. Leptin also improves glucose and lipid metabolism. We examined the short-term impact of olanzapine, a commonly used second-generation antipsychotic, on the central leptin-mediated regulation of energy balance, lipid metabolism, and hypothalamic kinase activity. Male Sprague Dawley rats were given an acute intracerebroventricular (ICV, 3rd ventricle) injection of either leptin or vehicle, combined with subcutaneous olanzapine or vehicle. As expected, ICV leptin decreased food intake and importantly, olanzapine did not block this effect. Administration of leptin, olanzapine, or their combination reduced the average respiratory exchange ratio (RER) during the light cycle, which indicates that fat oxidation was increased. In the dark cycle, leptin decreased the average RER regardless of olanzapine administration, and in the presence of leptin, olanzapine did not affect the average RER. Leptin did not alter the olanzapine-induced increase in serum triglyceride concentrations. Olanzapine and central leptin treatment differentially activated hypothalamic kinases. In conclusion, regulation of food intake and fuel preference by central leptin is intact following acute olanzapine administration.

neuroscience↗

bioRxiv2023

Immunogenicity and efficacy of a subcutaneously administered, adjuvanted vaccine containing modified S1 spike protein of SARS-CoV-2 variant C.1.2

During the COVID-19 pandemic, vaccines have produced protective immunity sufficient enough to cause a decrease in hospitalizations and deaths; however, the pandemic continues due to mutational events, predominantly occurring in the S1 sequence of the spike protein of SARS-CoV-2. We have developed a baculovirus-expressed, modified S1 SARS-CoV-2 protein based on the C.1.2 variant, which was first identified in South Africa.1 This was encapsulated in a vitamin E containing, nonphospholipid liposome, which was then used to subcutaneously immunize Syrian hamsters. This vaccine, when administered at day 1 generates IgG responses that react to the modified C.1.2 S1 protein; full-length spike proteins from Wuhan-Hu-1, Delta, Omicron BA.1; and the Omicron recombinant variant XBB.1.5 in 100% of the animals. The second dose administered subcutaneously on day 28 demonstrated anamnestic response in the quantitative IgG assay to the Wuhan-Hu-1 spike Receptor Binding Domain (RBD). In addition, antibody IgA and IgM responses in sera were demonstrated. Serum IgG antibody responses to the spike proteins of the modified C.1.2 S1 and full-length spike proteins Wuhan-Hu-1, Delta, Omicron BA.1, and Omicron recombinant XBB.1.5 variants are elevated for over 120 days. Challenge of vaccinated and unvaccinated hamsters at day 126 of the study with an Omicron BA.1 resulted in a difference in weight change and viral load based on the qRT-PCR assay seven days after challenge.

immunology↗

bioRxiv2022

An increase in serial sarcomere number induced via weighted downhill running improves work loop performance in the rat soleus

Increased serial sarcomere number (SSN) has been observed in rats via downhill running training due to the emphasis on active lengthening contractions; however, little is known about the influence on dynamic contractile function. Therefore, we employed 4 weeks of weighted downhill running training in rats, then assessed soleus SSN and work loop performance. We hypothesized trained rats would produce greater net work output during faster, higher-strain work loops due to a greater SSN. Thirty-one Sprague-Dawley rats were assigned to a control or training group. Weight was added during downhill running via a custom-made vest, progressing from 5-15% body mass. Following sacrifice, the soleus was dissected, and a force-length relationship was constructed. Work loops (active shortening followed by passive lengthening) were then performed about optimal muscle length (LO) at 1.5-3-Hz cycle frequencies and 1-7-mm strains to assess net work output. Muscles were then fixed in formalin at LO. Fascicle lengths and sarcomere lengths were measured and used to calculate SSN. Intramuscular collagen content and crosslinking were quantified via a hydroxyproline content and pepsin-solubility assay. Trained rats had longer fascicle lengths (+13%), greater SSN (+8%), greater specific active forces (+50%), and lower passive forces (-45-62%) than controls (P<0.05). There were no differences in collagen parameters (P>0.05). Net work output was greater (+101-424%) in trained than control rats for the 1.5-Hz loops at 1, 3, and 5-mm strains (P<0.05) and showed relationships with fascicle length (R2=0.14-0.24, P<0.05). These results suggest training-induced longitudinal muscle growth may improve dynamic performance.

physiology↗

bioRxiv2020

Cardiac CapZ regulation during acute exercise

PurposeExercise requires a rapid cardiac response to maintain cardiovascular function. CapZ is a critical stress-response protein in cardiac myocytes. While its role in the pathological stress response has been explored, its part in the physiological response to exercise is unknown. This study examined CapZ regulation during acute exercise and sought to determine its importance in the cardiac response to exercise. MethodsWildtype or cardiac CapZ-deficient transgenic mice were subjected to 20 min of swimming, or exhaustive exercise protocols. Time to exhaustion was a measurement of exercise capacity. Following submaximal exercise, cardiac myofilaments were isolated and probed for CapZ and key regulatory proteins. Myofilament function was assessed using an actomyosin MgATPase assay and total protein phosphorylation quantified with ProQ Diamond staining. Myofilament regulatory proteins following submaximal exercise were quantified by immunoblotting. ResultsTotal myofilament CapZ was unaffected by exercise but increased total CapZIP and decreased phosphorylated CapZIP indicated weakened CapZ-actin interaction. CapZ-deficient transgenic myofilaments lacked changes in CapZIP but BAG3 increased 10%. Time to exhaustion was lower in CapZ-deficient mice in both swimming and running protocols. Actomyosin MgATPase activity was maintained in wildtype mice and impaired with CapZ deficiency. Exercise increased the phosphorylation of several myofilament proteins in wildtype mice but not transgenic animals. Exercise-dependent Increases in myofilament PKC- and -{varepsilon} were mitigated in CapZ-deficient mice. Tcap levels decreased 39 {+/-} 8% in CapZ-deficient myofilaments with exercise and leiomodin 2 increased 78 {+/-} 28% in wildtype myofilaments. ConclusionsCardiac CapZ is a critical player in the physiological response to exercise. CapZ-actin binding is rapidly altered with exercise. Decreased cardiac CapZ limits exercise capacity, impairs myofilament regulation, and leads to a less stable contractile apparatus.

physiology↗