Biology subjects

Zubcevic, J.

Publications and source records attributed to Zubcevic, J..

5 recordsLinked to original sources

bioRxiv2026

Loss of Bone Marrow β1/β2-Adrenergic Receptors Reprograms Host-Microbiota Interactions and Protects Against Diet-Induced Obesity

The gut ecosystem is shaped by multiple factors with the immune system being one of the major determinants in shaping its composition in health and disease. On the other hand, the immune system regulates its responses through the action of the sympathetic nervous system (SNS) in part through beta-adrenergic receptors 1/2 (ADRB1/2). In the past years, a clear link has been established between the immune system, SNS, and the modification of nutrient absorption by the gut microbiota in the development of diet-induced obesity. We have previously shown in male mice transplanted with bone marrow cells ADRB1/2 knock-out mice (KD) showed mild immunosuppression and microbiota changes. Post-recovery, mice were challenged with high-fat diet (HFD) for two weeks ad libitum. Our findings show that KD mice are protected against diet-induced adiposity and weight gain. Additionally, these mice showed an increase in residual calorific values and a decreased expression of the fatty acid transporter FAT/CD36. Suggesting a decreased absorption of lipids in the KD mice. Gut microbiota analysis showed that KD microbiota composition on a HFD remained stable with a significant enrichment in the Bacteroidetes phylum, which is depleted in obesity. This was associated with a switch from triglycerides to diglyceride fecal profile. Moreover, microbiome culture showed a decrease in triglycerides after an incubation with 0.1% of HFD lipid extract. Suggesting a potential role of the Bacteroidetes phylum in the metabolism of these lipids. Our findings demonstrate not only that the gut microbiota can modify nutrient absorption and susceptibility to diet-induced obesity but also that the immune system contributes to selective depletion of microbial members that would otherwise thrive on dietary lipids. Revealing a novel mechanism by which host immunity sculpts the gut ecosystem in ways that influence metabolic outcomes.

physiology↗

bioRxiv2026

The mood stabilizer lithium alters behaviour and physiology via the gut brain axis.

Lithium, introduced 75 years ago by John Cade1, remains the most effective mood stabilizer for bipolar disorder2. Lithium is proposed to modulate an array of cellular pathways, many ubiquitous to all cells, with pleiotropic roles unlinked to bipolar disorder or lithium responsiveness in genome-wide association studies3,4. These mechanisms cannot explain lithiums specific effects on mood and behaviour. We demonstrate that lithiums primary action is in the periphery, not in the brain itself. Lithium acts in the gut to trigger behavioural and physiological changes, akin to those associated with a torpor-like state, that protect individuals from ingested toxins. Lithium activates gastrointestinal enterochromaffin (EC) cells via their Trpm2 cation channels to modulate afferent vagal and area postrema inputs to the brain. Eliminating these inputs by focal brain lesions eliminates lithiums effects, as does ablation of EC cells or their Trpm2 expression. Lithiums Trpm2-dependent activation of EC cells also occurs in human gut tissue, providing translational relevance for our discovery. These findings challenge the prevailing perception that lithium acts directly on the brain. Via a previously unsuspected gut-brain pathway, lithium engages brain circuitry that reduces arousal and interaction with the external world, therapeutic goals in the manic phase of bipolar disorder.

neuroscience↗

bioRxiv2024

Intestinal serotonergic vagal signaling as a mediator of microbiota-induced hypertension

Hypertension is a pervasive global health challenge, impacting over a billion individuals worldwide. Despite strides in therapeutic strategies, a significant proportion of patients remain resistant to the currently available therapies. While conventional treatments predominantly focus on cardiac, renal, and cerebral targets, emerging research underscores the pivotal role of the gut and its microbiota. Yet, the precise mechanisms governing interactions between the gut microbiota and the host blood pressure remain unclear. Here we describe a neural host-microbiota interaction that is mediated by the intestinal serotonin (5-HT) signaling via vagal 5HT3a receptors and which is crucial for maintenance of blood pressure homeostasis. Notably, a marked decrease in both intestinal 5-HT and vagal 5HT3aR signaling is observed in hypertensive rats, and in rats subjected to fecal microbiota transplantation from hypertensive rats. Leveraging an intersectional genetic strategy in a Cre rat line, we demonstrate that intestinal 5HT3aR vagal signaling is a crucial link between the gut microbiota and blood pressure homeostasis and that recovery of 5-HT signaling in colon innervating vagal neurons can alleviate hypertension. This paradigm-shifting finding enhances our comprehension of hypertensive pathophysiology and unveils a promising new therapeutic target for combating resistant hypertension associated with gut dysbiosis.

physiology↗

bioRxiv2020

Ghrelin signaling regulates feeding behavior, metabolism, and memory through the vagus nerve

Vagal afferent neuron (VAN) signaling sends information from the gut to the brain and is fundamental in the neural control of feeding behavior and metabolism. Recent findings reveal that VAN signaling also plays a critical role in cognitive processes, including hippocampus (HPC)-dependent memory. VANs, located in nodose ganglia, express receptors for various gut-derived endocrine signals, however, the function of these receptors with regards to feeding behavior, metabolism, and memory control is poorly understood. We hypothesized that VAN-mediated processes are influenced by ghrelin, a stomach-derived orexigenic hormone, via communication to its receptor (growth hormone secretagogue receptor [GHSR]) expressed on gut-innervating VANs. To examine this hypothesis, rats received nodose ganglia injections of an adeno-associated virus (AAV) expressing short hairpin RNAs targeting GHSR (or a control AAV) for RNA interference-mediated VAN-specific GHSR knockdown. Results reveal that VAN GHSR knockdown induced various feeding and metabolic disturbances, including increased meal frequency, impaired glucose tolerance, delayed gastric emptying, and increased body weight compared to controls. Additionally, VAN-specific GHSR knockdown impaired HPC-dependent episodic contextual memory and reduced HPC brain-derived neurotrophic factor expression, but did not affect anxiety-like behavior or levels of general activity. A functional role for endogenous VAN GHSR signaling was further confirmed by results revealing that VAN signaling is required for the hyperphagic effects of ghrelin administered at dark onset, and that gut-restricted ghrelin-induced increases in VAN firing rate require intact VAN GHSR expression. Collective results reveal that VAN GHSR signaling is required for both normal feeding and metabolic function as well as HPC-dependent memory.

neuroscience↗

bioRxiv2019

Attenuated amiloride-sensitive current and augmented calcium-activated chloride current in marsh rice rat (Oryzomys palustris) airways

Prolonged heat and sea salt aerosols pose a challenge for the mammalian airway, placing the protective airway surface liquid (ASL) at risk for desiccation. Thus, mammals inhabiting salt marshes might have acquired adaptations for ASL regulation. We studied the airways of the rice rat, a rodent that inhabits salt marshes. We discovered negligible Na+ transport through the epithelial sodium channel (ENaC). In contrast, carbachol induced a large Cl- secretory current that was blocked by the calcium-activated chloride channel (CaCC) inhibitor CaCCinh-A01. Decreased mRNA expression of , {beta}, and {gamma} ENaC, and increased mRNA expression of the CaCC transmembrane member 16A distinguished the rice rat airway. Rice rat airway cultures also secreted fluid in response to carbachol and displayed an exaggerated expansion of the ASL volume when challenged with 3.5% NaCl. These data suggest that the rice rat airway might possess unique ion transport adaptations to facilitate survival in the salt marsh environment.

physiology↗