Biology subjects

Buchanan, E.

Publications and source records attributed to Buchanan, E..

3 recordsLinked to original sources

bioRxiv2026

Short- and Long-Term Effects of Social Isolation on Adult Murine Bone are Sex-Dependent

Social isolation is a known modifiable risk factor for many chronic diseases including cardiovascular, metabolic, and neurological disorders. Recent research has demonstrated that social isolation is similarly detrimental to skeletal health, but these effects may be sexually dimorphic. In rodents, isolation negatively affects bone in adult male mice, but not in females. However, these sex differences have not been systematically investigated, and it is unknown if they persist with long-term social isolation. The goal of our study was to investigate if isolation-induced bone loss may occur on different timescales between female and male mice, as well as investigate the potential roles of estrogen and testosterone. We examined bone changes in grouped (4 mice/cage) or isolated (1 mouse/cage) female and male 16-week-old C57BL/6J mice after 2, 4, or 8 weeks of treatment. We found that social isolation through single housing significantly reduced bone parameters across treatment lengths in male mice (20% average reduction in Tb.BV/TV; 8% average reduction in Ct.Th.) but not in females even with prolonged isolation. In trabecular bone, isolation affected male bone parameters in as little as 2 weeks. Isolation also decreased biomechanical properties in the femur of male but not female mice. While the females overall bone phenotype was unaffected, isolated females did show an increase in bone turnover markers with 2 weeks of isolation. Isolation also altered estrogen-related gene expression in male mice isolated for 4 or 8 weeks. Overall, our results demonstrate that both short- and long-term social isolation has sexually dimorphic effects on murine bone. These findings have important clinical implications for individuals at risk for social isolation, as well as for pre-clinical rodent models utilizing single housing. Lay SummarySocial isolation may have worse effects on bone in males than females, but this has not been thoroughly explored. We investigated if different lengths of isolation had different effects on the bones of male and female mice. We found that both short- and long-term isolation had a rapid and negative impact on the bones of male but not female mice, although isolated females did show some changes in markers of bone formation and resorption. These findings have important implications for humans at risk for social isolation, as well as for studies with rodents that use single housing.

physiology↗

bioRxiv2022

Molecular autism research in Africa: a scoping review comparing publication outputs to Brazil, India, the UK, and the USA.

The increased awareness of autism spectrum disorders (ASD) is accompanied by burgeoning ASD research, and concerted research efforts are trying to elucidate the molecular ASD aetiology. However, much of this research is concentrated in the Global North, with recent reviews of research in Sub-Saharan Africa (SSA) highlighting the significant shortage of ASD publications from this region. The most limited focus area was molecular research with only two molecular studies ever published from SSA, both being from South Africa (SA). We examine the molecular ASD research publications from 2016 to 2021 from all African countries, with a special focus on SA. The SSA publications are compared to Brazil and India, two non-African, low-to-middle-income countries (LMICs), and to the UK and USA, two high-income countries (HICs). There were 228 publications across all regions of interest; only three publications were from SA. Brazil (n=29) and India (n=27) had almost 10 times more publications than SA. The HICs had more publications than the LMICs, with the UK (n=62) and the USA (n=74) having approximately 20 to 25 times more publications than SA, respectively. Given that SA has substantial research capacity as demonstrated by its recent research on SARS-CoV-2, we explore potential reasons for this deficit in molecular ASD publications from SA. We compare mental health research outputs, GDP per capita, research and development expenditure, and the number of psychiatrists and child psychiatrists per 100,000 people across all regions. The UK and the USA had significantly higher numbers for all these indicators, consistent with their higher publication output. Among the LMICs, SA can potentially produce more molecular ASD research, however, there are numerous barriers that need to be addressed to facilitate increased research capacity. These include cultural stigmas, challenges in accessing mental healthcare, shortages of specialists in the public sector, and the unreliability of ASD diagnostic tools across the 11 official SA languages. The unique genetic architecture of African populations presents an untapped reservoir for finding novel genetic loci associated with ASD. Therefore, addressing the disparity in molecular ASD research between the Global North and SSA is integral to global advancements in ASD research.

molecular biology↗

bioRxiv2021

DNA methylation of PGC-1α is associated with elevated mtDNA copy number and altered urinary metabolites in Autism Spectrum Disorder

BackgroundAutism Spectrum Disorder (ASD) is a complex disorder that is underpinned by numerous dysregulated biological pathways, including canonical mitochondrial pathways. Epigenetic mechanisms contribute to this dysregulation and DNA methylation is an important factor in the aetiology of ASD. We examined the relationship between DNA methylation of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1), an essential transcriptional regulator of mitochondrial homeostasis, and mitochondrial dysfunction in an ASD cohort of South African children. ResultsUsing targeted Next Generation bisulfite sequencing, we found 12 highly variable CpG sites in PGC-1 that were significantly differentially methylated (p<0.05) between ASD (n = 55) and controls (n = 44). In ASD, eight CpG sites were hypermethylated in the PGC-1 promotor with a putative binding site for CAMP response binding element 1 (CREB1) spanning one of these CpG sites (p = 1 x 10-6). Mitochondrial DNA (mtDNA) copy number, a marker of mitochondrial function, was elevated (p = 0.002) in ASD compared to controls and correlated significantly with DNA methylation at the PGC-1 promoter. There was a positive correlation between methylation at PGC-1 at CpG#1 and mtDNA copy number (Spearmans r = 0.2, n = 49, p = 0.04) in ASD, but a negative correlation between methylation at PGC-1 at CpG#4 promoter and mtDNA copy number in controls (Spearmans r = -0.4, n = 42, p = 0.045). While there was no relationship between mtDNA deletions and PGC-1 methylation in ASD, mtDNA deletions correlated negatively with methylation at PGC-1 at CpG#4 (Spearmans r = -0.4, n = 42, p = 0.032) in controls. Furthermore, levels of urinary organic acids associated with mitochondrial dysfunction correlated significantly (p<0.05) with DNA methylation at PGC-1 CpG#1 and mtDNA copy number in ASD (n= 20) and controls (n= 13) with many of these metabolites involved in altered redox homeostasis and neuroendocrinology. ConclusionsThese data show an association between PGC-1 promoter methylation, elevated mtDNA copy number and metabolomic evidence of mitochondrial dysfunction in ASD. This highlights an unexplored link between DNA methylation and mitochondrial dysfunction in ASD.

neuroscience↗