Biology subjects

Parnet, P.

Publications and source records attributed to Parnet, P..

3 recordsLinked to original sources

bioRxiv2026

Grey mouse lemurs, Microcebus murinus, are a relevant model to study gut microbiome flexibility in response to diet changes

The gut microbiota is a key player in energy balance, impacting both digestion efficiency and the production of metabolites involved in metabolism. Its composition is highly adaptable, especially in response to diet. Changes in human diet and lifestyle over time - from active, fibre-rich diets to sedentary habits with calorie-dense foods - have likely contributed to the rise in metabolic diseases. Rodent models are widely used to study the links between diet, microbiota and metabolism. However, they have important limitations (e.g. artificial environments, uniform diets and biological differences from humans) which can affect the translation of findings to humans. While mice and humans differ in their microbiota species, they do share some functional similarities. The grey mouse lemur (Microcebus murinus) has been proposed as a promising alternative model. This small primate experiences strong seasonal changes in food availability, leading to distinct physiological states (energy-saving in winter vs active in summer), even in captivity. It is increasingly recognized as a valuable model for biomedical research, supported by recent genomic and molecular advances. However, its gut microbiota has not yet been the subject of study. Consequently, the present study focuses on investigating the gut microbiota of the grey mouse lemur, with a particular emphasis on how these microbiota vary under different dietary regimens. The microbiota of animals fed the standard colony diet was dominated by Prevotella, Bifidobacterium, Megamonas, Streptococcus, Megasphaera and Lactococcus, showing an Prevotella driven enterosignature. We showed that switch from a classical control diet to 3 different diets resulted in change on microbiota composition that is associated with functional redundancy. The present work underline the interest of Microcebus murinus as model for diet and lifestyle studies in relationship with metabolic diseases.

microbiology↗

bioRxiv2025

Maternal low protein diet alters the development of reward circuits from childhood to adulthood by reshaping its function

Inadequate nutrition during pregnancy can lead to intrauterine growth retardation and low birth weight, which in turn increases the risk of developing metabolic disorders in adulthood, according to various epidemiological and clinical studies. The inclination of individuals born with low birth weight towards palatable foods indicates a possible modification in the hedonic aspect of their eating behavior. However, our understanding of the ontogenesis of structural organization and function within the brains reward circuits remains limited. Therefore, the objective of this research is to investigate the preferences for palatable food, molecular signatures of reward circuits, and functional properties of the nucleus accumbens (NAc) in a rat model of perinatal protein restriction (LP). Starting from weaning, continuing into adolescence and adulthood, a longitudinal analysis was conducted on rats born to mothers with protein-restricted diets during gestation and lactation (LP pups), comparing them to pups born from control dams (CD pups). The LP group exhibited an increased preference for palatable food at day 25 after birth (P25), followed by a decreased preference during adolescence (P50), and no significant difference in palatable food preference at P95 (young adult) compared to CD rats. Molecular and electrophysiological assessments of medium spiny neurons (MSN) in the NAc revealed a reorganization of reward circuits during crucial developmental periods, potentially influencing the attractiveness of palatable food for the LP group. This study represents the first exploration of how preferences for palatable food evolve throughout an individuals lifespan and how these observations correlate with the remodeling of reward circuits. By shedding light on the molecular and functional aspects of reward circuits, we contribute to a better understanding of the link between perinatal nutrition, behavioral preferences, and the underlying neural mechanisms.

neuroscience↗

bioRxiv2022

Cholecystokinin exerts a major control on corticostriatal synapse and motor behavior

Cholecystokinin (CCK) is a neuropeptide detected and produced at high concentrations in the brain. To date it was mainly used as a neuronal marker of neuronal subtypes and its role as a neuromodulator was poorly known. However, few studies showed that it could be an essential neuromodulator in various brain structures, playing a role on synaptic plasticity and memory consolidation. In order to better understand the processes by which CCK impacts plasticity, we focus our attention on the striatum, a nucleus involved in procedural learning and motor behavior, with a rich expression of CCK receptor type 2 (CCK2R). By using in-vivo and ex-vivo electrophysiological approaches, we show that CCK is involved in the corticostriatal synaptic transmission and has a key role in its plasticity. Using in-vivo optopatch-clamp of identified MSNs, we observe a decrease of corticostriatal synaptic transmission after an injection of CCK2R antagonist, leading to a reduction of evoked excitatory post synaptic potential recorded on both MSNs populations (direct and indirect pathways). In addition, we evaluate the impact of CCK2R antagonist on corticostriatal synaptic plasticity using Spike Timing Dependent Plasticity (STDP) protocols on MSNs of acute rat brain slices. Results demonstrate that the CCK2R antagonist is able to reverse the corticostriatal synaptic plasticity (i.e. LTP protocol leads to LTD). Finally, we evaluate the effect of CCK2R antagonist on the motor behavior of juvenile rats challenged with different locomotor tests and show a sex-dependent impairment of motor behavior. Overall, our results demonstrate that CCK and its receptor CCK2R are essential for inputs processing encoding in the corticostriatal network with consequences on motor activity. Significant statementCholecystokinin (CCK) is considered to be one of the most abundant neuropeptides in the brain but its role as a neuromodulator is not well understood. In our study we investigate its role on the corticostriatal transmission which is a well characterized synapse highly involved in motor and cognitive functions. Here, we show that CCK2R is crucial for the corticostriatal synaptic transmission and plasticity. Indeed, CCK binding on CCK2R is essential for LTP induction by STDP. Finally, we demonstrate that the blockage of CCK2R affects corticostriatal synaptic transmission and motor ability in male rats.

neuroscience↗