Identifying factors that influence stress physiology of the woylie, a critically endangered marsupial

Faecal glucocorticoid metabolites are minimally invasive stress physiology indices that can be used to understand how animals respond to physical and/or psychological challenges (stressors) and inform how to optimize conservation management in view of these stressors. We investigated contextual biological, environmental and parasitological factors influencing variation in baseline faecal cortisol metabolite (FCM) concentration in a critically endangered marsupial, the woylie (syn. brush-tailed bettong, Bettongia penicillata). Woylies have undergone a rapid and significant population decline, with environmental stressors exacerbating disease suggested to contribute to these ongoing declines. We conducted a longitudinal field study of 15 adult woylies (9 females, 6 males) in a captive, naturalistic facility. FCM concentration in faecal samples (n = 269) collected monthly over 20 months was quantified by enzyme immunoassay in parallel with measures of body condition, sex, season, female reproductive status and the presence of endoparasites and ectoparasites. Linear mixed effect modelling revealed a significant effect of season, sex, body condition index and nematode parasite status on FCM. Overall, mean FCM was lowest in summer and highest in autumn and winter, and females had higher mean FCM than males. There was a significant but weak negative association between body condition and FCM. When woylies were shedding oxyurid nematode eggs they had higher mean FCM compared to when they were not shedding. In future, knowledge of factors that influence FCM fluctuations in woylies may be considered when carrying out potentially stressful conservation interventions that may influence the future survival of this unique and threatened species

The Functional PTPN22 Variant R620W Is Strongly Associated With Giant Cell Artetitis Predisposition

Pathophysiology and treatment of rheumatic disease

Identification of the PTPN22 functional variant R620W as susceptibility genetic factor for giant cell arteritis

Pathophysiology and treatment of rheumatic disease

Risk loci involved in giant cell arteritis susceptibility: a genome-wide association study

Background Giant cell arteritis is an age-related vasculitis that mainly affects the aorta and its branches in individuals aged 50 years and older. Current options for diagnosis and treatment are scarce, highlighting the need to better understand its underlying pathogenesis. Genome-wide association studies (GWAS) have emerged as a powerful tool for unravelling the pathogenic mechanisms involved in complex diseases. We aimed to characterise the genetic basis of giant cell arteritis by performing the largest GWAS of this vasculitis to date and to assess the functional consequences and clinical implications of identified risk loci. Methods We collected and meta-analysed genomic data from patients with giant cell arteritis and healthy controls of European ancestry from ten cohorts across Europe and North America. Eligible patients required confirmation of giant cell arteritis diagnosis by positive temporal artery biopsy, positive temporal artery doppler ultrasonography, or imaging techniques confirming large-vessel vasculitis. We assessed the functional consequences of loci associated with giant cell arteritis using cell enrichment analysis, fine-mapping, and causal gene prioritisation. We also performed a drug repurposing analysis and developed a polygenic risk score to explore the clinical implications of our findings. Findings We included a total of 3498 patients with giant cell arteritis and 15 550 controls. We identified three novel loci associated with risk of giant cell arteritis. Two loci, MFGE8 (rs8029053; p=4·96 × 10–8; OR 1·19 [95% CI 1·12–1·26]) and VTN (rs704; p=2·75 × 10–9; OR 0·84 [0·79–0·89]), were related to angiogenesis pathways and the third locus, CCDC25 (rs11782624; p=1·28 × 10–8; OR 1·18 [1·12–1·25]), was related to neutrophil extracellular traps (NETs). We also found an association between this vasculitis and HLA region and PLG. Variants associated with giant cell arteritis seemed to fulfil a specific regulatory role in crucial immune cell types. Furthermore, we identified several drugs that could represent promising candidates for treatment of this disease. The polygenic risk score model was able to identify individuals at increased risk of developing giant cell arteritis (90th percentile OR 2·87 [95% CI 2·15–3·82]; p=1·73 × 10–13). Interpretation We have found several additional loci associated with giant cell arteritis, highlighting the crucial role of angiogenesis in disease susceptibility. Our study represents a step forward in the translation of genomic findings to clinical practice in giant cell arteritis, proposing new treatments and a method to measure genetic predisposition to this vasculitis