Cold exposure-induced alterations in the brain peptidome and gut microbiome are linked to energy homeostasis in mice

Cocaine-Induced Remodeling of the Rat Brain Peptidome: Quantitative Mass Spectrometry Reveals Anatomically Specific Patterns of Cocaine-Regulated Peptide Changes

Addiction to psychostimulants, including cocaine, causes widespread morbidity and mortality and is a major threat to global public health. Currently, no pharmacotherapies can successfully treat psychostimulant addiction. The neuroactive effects of cocaine and other psychostimulants have been studied extensively with respect to their modulation of monoamine systems (particularly dopamine); effects on neuropeptide systems have received less attention. Here, we employed mass spectrometry (MS) methods to characterize cocaine-induced peptidomic changes in the rat brain. Label-free peptidomic analysis using liquid chromatography coupled with tandem MS (LC-MS/MS) was used to describe the dynamic changes of endogenous peptides in five brain regions (nucleus accumbens, dorsal striatum, prefrontal cortex, amygdala, and hypothalamus) following an acute systemic cocaine challenge. The improved sensitivity and specificity of this method, coupled with quantitative assessment, enabled the identification of 1376 peptides derived from 89 protein precursors. Our data reveal marked, region-specific changes in peptide levels in the brain induced by acute cocaine exposure, with peptides in the cholecystokinin and melanin-concentrating hormone families being significantly affected. These findings offer new insights into the region-specific effects of cocaine and could pave the way for developing new therapies to treat substance use disorders and related psychiatric conditions.

The Role of Insulin Within the Socio-Psycho-Biological Framework in Type 2 Diabetes-A Perspective from Psychoneuroimmunology

The interplay between socio-psychological factors and biological systems is pivotal in defining human health and disease, particularly in chronic non-communicable diseases. Recent advancements in psychoneuroimmunology and mitochondrial psychobiology have emphasized the significance of psychological factors as critical determinants of disease onset, progression, recurrence, and severity. These insights align with evolutionary biology, psychology, and psychiatry, highlighting the inherent social nature of humans. This study proposes a theory that expands insulin's role beyond traditional metabolic functions, incorporating it into the Mitochondrial Information Processing System (MIPS) and exploring it from an evolutionary medicine perspective to explore its function in processing psychological and social factors into biological responses. This narrative review comprises data from preclinical animal studies, longitudinal cohort studies, cross-sectional studies, machine learning analyses, and randomized controlled trials, and investigates the role of insulin in health and disease. The result is a proposal for a theoretical framework of insulin as a social substance within the socio-psycho-biological framework, emphasizing its extensive roles in health and disease. Type 2 Diabetes Mellitus (T2DM) with musculoskeletal disorders and neurodegeneration exemplifies this narrative. We suggest further research towards a comprehensive treatment protocol meeting evolutionary expectations, where incorporating psychosocial interventions plays an essential role. By supporting the concept of 'insulin resilience' and suggesting the use of heart rate variability to assess insulin resilience, we aim to provide an integrative approach to managing insulin levels and monitoring the effectiveness of interventions. This integrative strategy addresses broader socio-psychological factors, ultimately improving health outcomes for individuals with T2DM and musculoskeletal complications and neurodegeneration while providing new insights into the interplay between socio-psychological factors and biological systems in chronic diseases.

Native Mass Spectrometry-Centric Approaches Revealed That Neuropeptides Frequently Interact with Amyloid-β

Amyloid-β (Aβ) aggregates are recognized as initiators of Alzheimer's disease, and their interaction with the nervous system contributes to the progression of neurodegeneration. Herein, we investigated the frequency at which neuropeptides interact with Aβ and affect the aggregation kinetics and cytotoxicity of Aβ. To this end, we established a native mass spectrometry (MS)-centric workflow for screening Aβ-interacting neuropeptides, and six out of 12 neuropeptides formed noncovalent complexes with Aβ species in the MS gas phase. Thioflavin-T fluorescence assays and gel separation indicated that leptin and cerebellin decreased Aβ aggregation, whereas kisspeptin increased this process. In addition, leptin and cerebellin attenuated Aβ-induced cytotoxicity, which was independent of the influence of metal ions. Leptin can chelate copper from copper-bound Aβ species, reducing the cytotoxicity caused by the aggregation of Aβ and metal ion complexes. Overall, our study demonstrated that neuropeptides frequently interact with Aβ and revealed that leptin and cerebellin are potential inhibitors of Aβ aggregation, providing great insight into understanding the molecular mechanism of Aβ interacting with the nervous system and facilitating drug development.

Dietary-fat supplementation alleviates cold temperature-induced metabolic dysbiosis and barrier impairment by remodeling gut microbiota

As important components of the mammalian diet and tissues, fats are involved in a variety of biological processes in addition to providing energy. In general, the increase in basal metabolism and health risks under cold temperature conditions causes the host to need more energy to maintain body temperature and normal biological processes. The intestine and its microbiota are key components in orchestrating host metabolic homeostasis and immunity, and respond rapidly to changing environmental conditions. However, the role of dietary-fat supplementation in regulating host homeostasis of metabolism and barrier functions through gut microbiota at cold temperatures is incompletely understood. Our results showed that dietary-fat supplementation alleviated the negative effects of cold temperatures on the alpha-diversity of both ileal and colonic microbiota. Cold temperatures altered the ileal and colonic microbiota of pigs, and the extent of changes was more pronounced in the colonic microbiota. Translocation of the gut microbiota was restored after supplementation with a high-fat diet. In addition, cold temperatures exacerbated ileal mucosal damage and inflammation, and disrupted barrier function, which may be associated with decreased concentrations of butyrate and isobutyrate. Cold temperature-induced metabolic dysbiosis was manifested by altered hormone levels and upregulation of expression of multiple metabolites involved in metabolism (lipids, amino acids and minerals) and the immune response. Supplementation with a high-fat diet restored metabolic homeostasis and barrier function by improving gut-microbiota composition and increasing SCFAs concentrations in pigs. In conclusion, cold temperatures induced severe translocation of microbiota and barrier damage. These actions increased the risk of metabolic imbalance. Dietary-fat supplementation alleviated the adverse effects of cold temperatures on host metabolism by remodeling the gut microbiota.