Chronic stress and adipose tissue in the anorexic state: endocrine and epigenetic mechanisms

IL-17 signalling is critical for controlling subcutaneous adipose tissue dynamics and parasite burden during chronic murine Trypanosoma brucei infection

In the skin, Trypanosoma brucei colonises the subcutaneous white adipose tissue, and is proposed to be competent for forward transmission. The interaction between parasites, adipose tissue, and the local immune system is likely to drive the adipose tissue wasting and weight loss observed in cattle and humans infected with T. brucei. However, mechanistically, events leading to subcutaneous white adipose tissue wasting are not fully understood. Here, using several complementary approaches, including mass cytometry by time of flight, bulk and single cell transcriptomics, and in vivo genetic models, we show that T. brucei infection drives local expansion of several IL-17A-producing cells in the murine WAT, including TH17 and Vγ6+ cells. We also show that global IL-17 deficiency, or deletion of the adipocyte IL-17 receptor protect from infection-induced WAT wasting and weight loss. Unexpectedly, we find that abrogation of adipocyte IL-17 signalling results in a significant accumulation of Dpp4+ Pi16+ interstitial preadipocytes and increased extravascular parasites in the WAT, highlighting a critical role for IL-17 signalling in controlling preadipocyte fate, subcutaneous WAT dynamics, and local parasite burden. Taken together, our study highlights the central role of adipocyte IL-17 signalling in controlling WAT responses to infection, suggesting that adipocytes are critical coordinators of tissue dynamics and immune responses to T. brucei infection.

Identification of adipose tissue transcriptomic memory of anorexia nervosa

BACKGROUND

Anorexia nervosa (AN) is a complex debilitating disease characterized by intense fear of weight gain and excessive exercise. It is the deadliest of any psychiatric disorder with a high rate of recidivism, yet its pathophysiology is unclear. The Activity-Based Anorexia (ABA) paradigm is a widely accepted mouse model of AN that recapitulates hypophagia and hyperactivity despite reduced body weight, however, not the chronicity.

METHODS

Here, we modified the prototypical ABA paradigm to increase the time to lose 25% of baseline body weight from less than 7 days to more than 2 weeks. We used this paradigm to identify persistently altered genes after weight restoration that represent a transcriptomic memory of under-nutrition and may contribute to AN relapse using RNA sequencing. We focused on adipose tissue as it was identified as a major location of transcriptomic memory of over-nutririon.

RESULTS

We identified 300 dysregulated genes that were refractory to weight restroration after ABA, including Calm2 and Vps13d, which could be potential global regulators of transcriptomic memory in both chronic over- and under-nutrition.

CONCLUSION

We demonstrated the presence of peristent changes in the adipose tissue transcriptome in the ABA mice after weight restoration. Despite being on the opposite spectrum of weight perturbations, majority of the transcriptomic memory genes of under- and over-nutrition did not overlap, suggestive of the different mechanisms involved in these extreme nutritional statuses.

COVID-19 induced anorexia nervosa: A case series and brief review of literature

Key Clinical Message

This article emphasizes that patients presenting with COVID-19 infection especially presenting with predominantly gastrointestinal symptoms and a history of eating disorder or even other mental disorders should be evaluated thoroughly and differential diagnoses should be considered. Clinicians should keep in mind that eating disorders may happen after COVID infection or vaccination.

Abstract

The emergence and global spread of the 2019 novel coronavirus (COVID-19) have caused a significant mental health burden on communities around the world. Factors related to COVID-19 affect mental health in the general community, but may have more adverse effects on individuals with pre-existing mental illnesses. Additionally with the new living conditions and increased focus on hand hygiene and fear of contracting COVID-19, depression, anxiety, and obsessive-compulsive disorder (OCD) are more likely to be exacerbated. Eating disorders such as anorexia nervosa (AN) have exhibited an alarming increase due to social pressure especially through social media. Also, many patients reported relapses since the commencement of the COVID-19 pandemic. We report five cases of AN that developed or exacerbated after COVID-19 infection. Four patients have newly developed (AN) and one case relapsed after COVID-19 infection. Also, one of the patient's symptoms exacerbated after remission following a COVID-19 vaccine shot. The patients were managed medical and non-medically. Three of cases have reported improvements while two other cases were lost because of poor compliance. It might be possible that people with history of eating disorder, or other mental disorders may be more susceptible to newly develop or exacerbate eating disorders after COVID-19 infection especially when symptoms are gastrointestinal dominant. There is currently minimal evidence on the specific risk of COVID-19 infection in patients with AN and reporting cases of AN after COVID-19 infection could help learn the risk, prevent and manage patients. Clinicians should keep in mind that eating disorders may happen after COVID infection or vaccination.

LSD1 for the Targeted Regulation of Adipose Tissue

White and thermal (brown and beige) adipose tissue energy storage and oxidative regulation pathways play a central role in maintaining the energy balance throughout the body, and the dysregulation of these pathways is closely related to glucose and lipid metabolism disorders and adipose tissue dysfunction, including obesity, chronic inflammation, insulin resistance, mitochondrial dysfunction, and fibrosis. Recent epigenetic studies have identified the novel regulatory element LSD1, which controls the above parameters, and have provided new mechanistic possibilities for re-encoding the fate and function of adipocytes. In this review, we outline the current advances in adipocyte metabolism in physiology and disease and discuss possible strategies for LSD1 to alter the phenotype of adipose tissue and thus influence energy utilization to improve metabolic health.

ATP5O Hypo-crotonylation Caused by HDAC2 Hyper-Phosphorylation Is a Primary Detrimental Factor for Downregulated Phospholipid Metabolism under Chronic Stress

Objective. Chronic stress (CS)-induced abnormal metabolism and other subsequent aspects of abnormality are threatening human health. Little is known regarding whether and how protein post-translational-modifications (PTMs) correlate with abnormal metabolism under CS. The aim of this study was to address this issue and also identify novel key protein PTM. Methods. First, we screened which pan-PTM had significant change between control and CS female mice and whether clinical CS females had similar pan-PTM change. Second, we performed quantitative PTM-omics and metabolomics to verify the correlation between abnormal protein PTMs and atypical metabolism. Third, we performed quantitative phospho-omics to identify the key PTM-regulating enzyme and investigate the interaction between PTM protein and PTM-regulating enzyme. Fourth, we attempted to rectify the abnormal metabolism by correcting the activity of the PTM-regulating enzyme. Finally, we examined whether the selected key protein was also correlated with stress scores and atypical metabolism in clinical women. Results. We initially found that multiple tissues of CS female mice have downregulated pan-crotonylation, and verified that the plasma of clinical CS females also had downregulated pan-crotonylation. Then we determined that ATP5O-K51 crotonylation decreased the most and also caused gross ATP5O decrement, whereas the plasma of CS mice had downregulated phospholipids. Next, downregulating ATP5O crotonylation partially recapitulated the downregulated phospholipid metabolism in CS mice. Next, we verified that HDAC2-S424 phosphorylation determined its decrotonylation activity on ATP5O-K51. Furthermore, correcting HDAC2 hyper-phosphorylation recovered the gross ATP5O level and partially rescued the downregulated phospholipid metabolism in CS mice. Finally, the ATP5O level was also significantly lower and correlated with high stress scores and downregulated phospholipid metabolism in clinical female plasma. Conclusion. This study discovered a novel PTM mechanism involving two distinct types of PTM in CS and provided a novel reference for the clinical precautions and treatments of CS.

Time course and reaction types of serum IGF-1 and its relationship to BMI and leptin regarding inpatients with anorexia nervosa

OBJECTIVE

Anorexia nervosa (AN) is a severe mental disorder that is characterized by restriction of energy intake, low weight, and endocrine abnormalities. One of the known endocrine changes in relation to underweight is in the GH/IGF-I axis. The aim of the study was (a) to investigate longitudinal characteristics of the IGF-I-change during therapy and weight gain in adult AN, (b) to determine relationships between IGF-I and leptin, (c) to characterize patients with weak and pronounced hormonal reactions to underweight.

DESIGN

Data was assessed from 19 AN patients. Over the first two months, serum IGF-I concentrations were assessed on a weekly basis; thereafter on a monthly basis. The trend of IGF-I values over time was analyzed using individual growth models.

RESULTS

In total, n = 177 IGF-I measurements were analyzed. IGF-I increased significantly dependent on BMI (slope = 20.81, p < 0.001), not modulated by duration of disease. The increase in IGF-I was significantly related to the increase in leptin concentrations over time (slope = 15.57, p < 0.001). Patients with a weaker hormonal reaction to underweight were significantly older compared to patients with a pronounced hormonal reaction (t(17) = 3.07, p = 0.007).

CONCLUSIONS

During treatment, IGF-I change is clearly related to BMI as well as to leptin. Age appears to be associated with the IGF-I response to underweight.

Anorexia nervosa: COVID-19 pandemic period (Review)

Anorexia nervosa is an eating disorder characterized by restrictive eating and an intense fear of gaining weight. It is a disease with an increasing incidence during the last few decades, and represents a complex psychiatric condition which includes secondary amenorrhea, nutritional and metabolic damage, and impaired endocrine panel up to bone loss as well as cardiac, gastrointestinal and hematological complications. This is a narrative review which includes an update on this eating disorder from the perspective of an endocrine panel of anomalies, especially of the skeleton, considering the pressure of the recent global COVID-19 pandemic changes. Practically affecting every organ, anorexia nervosa needs to be taken into consideration during the pandemic period because of the higher risk of relapse due to new living conditions, social distancing, self-isolation, changes in food access, more intense use of social media platforms, disruption of daily habits, and more difficult access to healthcare practitioners. The lack of physical activity in addition to vitamin D deficiency related to low sun exposure or to the use of facial masks may also be connected to further bone damage related to this disease.