Biology subjects

Bondarenko, E.

Publications and source records attributed to Bondarenko, E..

5 recordsLinked to original sources

bioRxiv2024

Episodic slow breathing in mice markedly reduces fear responses

We sought to delineate neural mechanisms underlying the effects of controlled breathing in humans, such as in meditation or breathwork, which can reduce depression, anxiety, stress, and pain. Thus, we developed a murine model, where breathing frequency in awake mice can be substantially slowed. When done for 30 min/day for 4 weeks, these mice had significant reductions in stress-related changes in behavior compared to control mice. We conclude that slow breathing effects on emotional state are present in mice, and which cannot be attributed directly to top-down influences such as volitional or emotional control or placebo effects. Our study paves the way for investigations of the neural mechanisms underlying body-brain interactions related to the effects of controlled breathing as well as a platform for optimization of its therapeutic use for amelioration of ordinary and pathological stress and anxiety in humans.

neuroscience↗

bioRxiv2024

Proof of Concept for High-Dose Cannabidiol Pretreatment to Antagonize Opioid Induced Persistent Apnea

Using a mouse equivalent of FDA-approved cannabidiol (CBD) dosing, we found high dose CBD affects opioid induced persistent apnea (OIPA), the principal cause of opioid related fatalities. CBD pretreatment mitigated respiratory depression from fentanyl in awake mice and significantly delayed OIPA onset in anesthetized mice, effective as the opioid antagonist naloxone. The powerful effect of CBD pretreatment on OIPA suggests a novel therapeutic strategy to reduce fatal opioid overdose incidence.

physiology↗

bioRxiv2024

Sigh generation in preBötzinger Complex

We explored neural mechanisms underlying sighing. Photostimulation of parafacial (pF) neuromedin B (NMB) or gastrin releasing peptide (GRP), or preBotzinger Complex (preBotC) NMBR or GRPR neurons elicited ectopic sighs with latency inversely related to time from preceding endogenous sigh. Of particular note, ectopic sighs could be produced without involvement of these peptides or their receptors in preBotC. Moreover, chemogenetic or optogenetic activation of preBotC SST neurons induced sighing, even in the presence of NMBR and/or GRPR antagonists. We propose that an increase in the excitability of preBotC NMBR or GRPR neurons not requiring activation of their peptide receptors activates partially overlapping pathways to generate sighs, and that preBotC SST neurons are a downstream element in the sigh generation circuit that converts normal breaths into sighs.

neuroscience↗

bioRxiv2024

Comparative framework and adaptation of ACME HS approach to single cell isolation from fresh-frozen endocrine tissues

Current scRNA-seq studies of solid tissues mostly rely on enzymatic dissociation of fresh samples or the fallback on nuclei isolation from frozen or partially fixed samples. However, due to the complex tissue organization or cell fragility, it could be challenging to apply these approaches to the sensitive endocrine tissues. That is, dissociating intact cells from such problematic fresh-frozen samples routinely collected by biobanks remains challenging. In this study, we adapted the acetic-methanol dissociation method - ACME High Salt (ACME HS) to effectively isolate intact single cells from fresh-frozen endocrine tumor samples, including adrenal gland neoplasms, thyroid carcinomas, and pituitary neuroendocrine tumors. We compared the ability of enzymatic, ACME HS, and nuclear isolation methods to preserve the integrity of major cell types and gene expression across 41 tissue samples of different origins. We demonstrated that ACME HS simultaneously dissociates and fixes cells, thus preserving morphology and a high RNA integrity number in problematic cell types. This finding renders the ACME HS dissociation method a valuable alternative in scRNA-seq protocols for challenging tissues where obtaining live cell suspension is difficult or impossible.

genomics↗

bioRxiv2021

Phase- and State-Dependent Modulation of Breathing Pattern by preBötzinger Complex Somatostatin Expressing Neurons

As neuronal subtypes are increasingly categorized, delineating their functional role is paramount. The preBotzinger Complex (preBotC) subpopulation expressing the neuropeptide somatostatin (SST) is classified as mostly excitatory, inspiratory-modulated and not rhythmogenic. We further characterized their phenotypic identity; 87% were glutamatergic and the balance were glycinergic and/or GABAergic. We then used optogenetics to investigate their modulatory role in both anesthetized and freely moving mice. In anesthetized mice, short photostimulation (100 ms) of preBotC SST+ neurons modulated breathing-related variables in a combinatory phase- and state-dependent manner; changes in inspiratory duration, inspiratory peak amplitude (Amp), and phase were different at higher ([≥]2.5 Hz) vs. lower (<2.5 Hz) breathing frequency. Moreover, we observed a biphasic effect of photostimulation during expiration that is probabilistic, i.e., photostimulation given at the same phase in consecutive cycles can evoke opposite responses (lengthening vs. shortening of the phase). This unexpected probabilistic state- and phase-dependent responses to photostimulation exposed properties of the preBotC that were not predicted and cannot be readily accounted for in current models of preBotC pattern generation. In freely moving mice, prolonged photostimulation decreased f in normoxia, hypoxia, or hypercapnia, and increased Amp and produced a phase advance, which was similar to the results in anesthetized mice when f[≥]2.5 Hz. We conclude that preBotC SST+ neurons are a key mediator of the extraordinary and essential lability of breathing pattern. Key points summaryO_LIWe transfected preBotzinger Complex (preBotC) somatostatin-expressing (SST+) neurons, which modulate respiratory pattern, but are not rhythmogenic, with channelrhodopsin to investigate phase- and state-dependent modulation of breathing pattern in anesthetized and freely behaving mice in normoxia, hypoxia, and hypercapnia. C_LIO_LIIn anesthetized mice, photostimulation of preBotC SST+ neurons during inspiration increased inspiratory duration and amplitude regardless of baseline breathing frequency, f. C_LIO_LIIn anesthetized mice with low f (<2.5 Hz), photostimulation of preBotC SST+ neurons during expiration evoked either phase advance or phase delay, whereas in anesthetized mice with high f ([≥]2.5 Hz) and in freely behaving mice in normoxia, hypoxia, or hypercapnia, photostimulation always evoked phase advance. C_LIO_LIPhase- and state-dependency is a function of overall breathing network excitability. C_LIO_LIThe f-dependent probabilistic modulation of breathing pattern by preBotC SST+ neurons was unexpected, requiring reconsideration of current models of preBotC function, which neither predict nor can readily account for such responses. C_LI

neuroscience↗