The gut microbiome plays a crucial role in host physiology, including the production of a diverse array of metabolites that can enter the circulation and affect distant organs. Deoxycholic acid (DCA), a secondary bile acid produced by intestinal bacteria, may impact gastrointestinal function. Altered intestinal motility is implicated in a variety of gastrointestinal disorders, and understanding the direct effects of bacterial metabolites, such as DCA, on smooth muscle contractility is essential. This study aimed to investigate the direct impact of deoxycholic acid on the spontaneous and agonist-induced contractile activity of the small intestine. Full-thickness ileal strips were isolated from mice and mounted in an organ bath system containing oxygenated Krebs buffer. Contractile activity was measured via an external force displacement transducer and recorded with LabChart software. Tissues were treated with varying concentrations of DCA and compared to vehicle-treated controls. Both spontaneous and carbachol-induced contractile activity were assessed. Treatment with deoxycholic acid resulted in a significant dose-dependent reduction in the spontaneous contractile activity of the isolated mouse ileum, but did not affect carbachol-induced contractions. Deoxycholic acid, a key bacterial metabolite, acts as a potent inhibitor of intestinal motility by significantly reducing spontaneous contractile activity in the mouse ileum. This finding suggests that the gut microbiome, through its metabolic products, can modulate host gastrointestinal function and highlights DCA as a potential therapeutic target or diagnostic biomarker for motility disorders.

Témavezető: Dr. Uray Karen és keserű Szandi

Introduction: Huntington's disease (HD) is an autosomal-dominant neurodegenerative disorder caused by the abnormal expansion of CAG repeats in the first exon of the HTT gene. Although most research on HD focuses on the CNS, the mutant huntingtin protein is widely expressed in the body, and hence the disorder has systemic effects. Importantly, significant weight loss occurs early in the disease and often precedes other classical symptoms. Weight loss correlates with the number of CAG repeats. Acetylcholine, dopamine, and GABA levels, which influence gastric and intestinal motility, are altered in HD. Furthermore, enteric nervous system neurodegeneration, leading to altered gastrointestinal motility and inflammation, has been demonstrated in recent studies using R6/2 HD mice.Objective: The present study aims to investigate gastrointestinal morphology, physiology, and the molecular mechanisms underlying gastrointestinal dysmotility in HD, which are understudied and poorly understood in a transgenic mouse model of HD. Materials and methods: Hemizygous HD Exon1 R6/1 transgenic mice and wild-type (WT) mice were used. The contractility of the ileum and duodenum was measured using an ex vivo organ bath. Both spontaneous and carbachol (an acetylcholine agonist)- induced contractile activity were measured. Additionally, intestinal water content was also assessed from the collected samples by calculating wet-to-dry weight ratios. Results: Spontaneous integral and tone were significantly higher, and contraction amplitude was significantly lower in the ileum of female HD mice compared with their WT littermates. Upon carbachol treatment, contractile activity (calculated as the integral) was significantly higher in the duodenum of both HD males and females. The wet-to-dry ratios and the relaxation percentage were not statistically different between WT and HD mice. In addition, HD mice demonstrated significant weight loss compared to their WT littermates.Conclusions: The data suggest that HD alters basal contractility in female mice and carbachol-induced contractility in both genders. The altered basal intestinal motility is not due to impaired relaxation or edema development; however, it can explain the weight loss in HD mice and patients with HD.Our studies are ongoing to characterize the signaling pathway underlying smooth muscle contraction in the gastrointestinal tract of HD mice.

Témavezető: Dr. Tar Krisztina és Dr. Uray Karen Lee

Chronic polyneuropathy is one of the most common consequences of type 2 diabetes, leading to the development of neuropathic pain (DNP) in more than 30% of patients. First-line drugs used to treat DNP are often completely ineffective, indicating that the mechanism of DNP development is not fully understood. One of the hallmarks of central sensitization inducing chronic pain is reactive gliosis, which leads to interleukin 1 beta (IL-1β) and tumor necrosis factor alpha (TNFα)-dependent neuroinflammation. Methylglyoxal (MGO), a cytotoxic metabolite that accumulates in diabetic patients, serves as a model to investigate the contribution of metabolic alterations to reactive glial changes in the spinal dorsal horn (SDH), where primary pain processing occurs. To investigate MGO-induced changes in spinal astrocyte morphology and inflammatory cytokine production in a sex-dependent manner.Male and female mice received acute or subacute (1-week) MGO administration. Spinal cord tissue was analyzed for astrocyte morphology (branch length, branching points) and cytokine production (IL-1β, TNFα) using immunofluorescence and confocal microscopy.Acute MGO administration increased astroglial production of IL-1β in females and TNFα in males, without significant changes in astrocyte morphology. Notably, branch length and branching points remained unchanged or showed decreases. In contrast, subacute MGO treatment (1 week) significantly enhanced both astrocytic branch length and ramification in both sexes, indicating morphological activation and increased surveillance capacity.Our data indicate that MGO triggers sex-specific, time-dependent astroglial responses in the spinal dorsal horn characterized by differential cytokine production at acute timepoints and progressive morphological remodeling with prolonged exposure. We propose that in diabetic patients, accumulation of MGO can lead to the development of neuropathic pain through a two-phase mechanism: acute cell-dependent inflammatory signaling followed by sustained astroglial morphological remodeling. The sex-dependent character of the neuroinflammatory response, together with the distinct patterns of astrocytic ramification in males and females, underscores the need for better-targeted, sex-specific therapeutic approaches in diabetic neuropathic pain.

Témavezető: Dr. Hegyi Zoltan és Dr. Docs Klaudia

The cannabidiol (CBD) has antiepileptic actions by decreasing the excitability of hippocampal pyramidal cells. Besides treatment of epilepsy, the derivatives of CBD can be beneficial in other neurological and neuropsychiatric diseases such as autism spectrum disorder (ASD), schizophrenia, anxiety, neuropathic pain, Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, traumatic brain injury. However, the usage of CBD itself is limited by its low bioavailability and water solubility, as well as the risk of conversion to psychoactive compounds. To address these problems, it would be beneficial to replace CBD with derivatives having better water solubility and stability. The aim of the present project is to provide preliminary data for later comparison of the actions of CBD with newly synthesized derivatives.We performed whole-cell patch clamp experiments on CA1 hippocampal pyramidal cells in current clamp mode and investigated changes of the input resistance, rheobase current and firing rate. Next, we investigated the amplitude and frequency of inhibitory postsynaptic currents (IPSCs) on CA1 hippocampal pyramidal neurons. The input resistance and the rheobase current of pyramidal cells did not show marked changes, whereas the firing rate was significantly reduced. We also found that the IPSC amplitude and frequency did not reveal any significant increase if all events were considered. However, a population of events with greater amplitude appeared. In conclusion, we confirmed that the CBD decreases the firing rate and has a limited but detectable action on inhibitory inputs, acknowledging the literature findings. We can further compare its actions with newly synthesized derivatives to optimize its use in the treatment of neurological and neuropsychiatric diseases.

Témavezető: Dr. Pal Balazs és Dr. Bakai-Bereczki Ilona

Osteoarthritis (OA) is a degenerative joint disorder affecting approximately 595 million people worldwide, characterized by progressive cartilage degeneration and subchondral bone sclerosis, leading to disability and impaired quality of life. As a consequence of disability, sarcopenia and atrophy may develop in patients; however, these features are only minimally described in animal models.This study aimed to examine changes of muscle mass and performance in a surgically induced mouse model of OA. Furthermore, we aimed to determine whether unoperated or sham-operated knees serve as a more appropriate control of surgically induced OA. In wild-type C57BL/6 mice, OA was induced by destabilization of the medial meniscus (DMM), and the results were compared to sham-operated and unoperated controls eight weeks after surgery. In vivo muscle performance was assessed using running wheel, grip, hang, and rotarod tests. Weight and cross-sectional area of isolated tibialis anterior (TA), extensor digitorum longus and soleus muscles were measured. Subchondral bone microstructure was evaluated using high resolution (5 µm) micro-CT.Except for a slight reduction in TA weight after DMM, neither the sham nor DMM surgeries led to significant changes in muscle mass, cross-sectional area, or in vivo muscle performance. Micro-CT analysis showed that sham-operated knees underwent bone remodeling due to unloading, which was reflected by a loss of trabeculae compared with unoperated controls. In contrast, DMM operated knees exhibited subchondral bone sclerosis, a hallmark of OA, characterized by increased bone volume, thickness and connectivity. Although unloading likely occurred in both groups, sclerotic changes associated with OA were more prominent in DMM knees. Multivariate analyses (PCA and ANOSIM) based solely on bone parameters demonstrated that all three groups were significantly different, whereas analyses restricted to muscle mass and performance parameters revealed that the groups did not differ significantly. These findings emphasize the importance of proper study design, as minor surgical interventions can influence weight bearing and subchondral bone microstructure, and unoperated controls fail to capture certain key changes only detectable in the sham-operated animals. Additionally, although modest muscle wasting was observed in mid-term OA, no corresponding in vivo functional impairment was detected, allowing for a timely intervention in clinical practice.

Témavezető: Dr. Oláh Tamás

Simvastatin is a widely prescribed drug used to treat patients with hypercholesterolemia and hypertriglyceridemia. Though considered safe, myotoxicity is a known adverse effect, affecting approximately 1/10,000 patients. The endocannabinoid system (ECS) refers to a complex lipid cell signaling system with a significant role in human health and disease. The agonists are the two lipid mediators: anandamide (AEA) and 2-arachidonoylglycerol (2-AG), which activate two G protein-coupled receptors: CB1 and CB2, with distinct tissue-specific pattern expressions in the body. This study aimed to investigate the relationship between the skeletal ECS and the myopathic effects of simvastatin. Two murine models were used: Tamoxifen-inducible skeletal muscle–specific CB1 knockdown mice (Cre+/−) with littermate controls (Cre−/−), and global CB1 knockout mice (CB1−/−) with wild-type littermates (CB1+/+). Simvastatin was administered via oral gavage at a weight-adjusted dosage of 20 mg/kg for four weeks. In vivo measurement such as grip force, hang, and Rota-Rod tests, as well as in vitro isometric force measurement and intracellular calcium signaling assessed via whole-cell voltage clamping, were performed pre- and post-treatment. In vivo results indicated that while physiological aging generally led to increased force production across all groups, the absence of CB1 receptors exacerbated myopathic symptoms. Specifically, Cre+/- mice treated with simvastatin exhibited decreased muscle force compared to the simvastatin-treated Cre-/- controls. Similarly, statin-treated CB1-/- mice demonstrated lower normalized grip force than vehicle-treated wild-type mice. In the hang test, simvastatin treatment resulted in a decreased latency to fall in Cre-/-, Cre+/-, and CB1-/- mice. While vehicle-treated CB1-/- mice displayed an increased latency to fall, a protective benefit lost under statin treatment. Rota-Rod tests showed no significant drug-induced changes, likely due to aging-related learned progression masking the effects. In vitro measurements showed reduced isometric force in both fast- and slow-twitch muscles after statin treatment, while whole-cell patch clamp with confocal microscopy revealed mild changes in intracellular calcium signaling. These results indicate that skeletal muscle CB1 signaling plays a key role in simvastatin-induced myopathy, suggesting ECS pathways may influence individual risk for statin myopathy and serve as targets for protective therapies.

Témavezető: Dr. Sztretye Mónika és Dr. Singlár Zoltán

A Xenopus laevis petesejtek hosszú ideje szolgálnak kísérleti eszközként ioncsatornák, receptorok és transzporterek élettani vizsgálataihoz, mint olyan sejt, amely kifejezi (overexpress) a vizsgálandó fehérjét.. Kutatásunk célja az volt, hogy két elektródás voltage clamp (TEVC) módszerrel feltérképezzük, milyen membránáram- és membránpotenciál-változásokat vált ki különböző hullámhosszúságú fény a Xenopus laevis petesejtekben, különösen a kék tartományba eső megvilágítás. A fény által kiváltott áramváltozások jelensége korábbi publikációkban is megjelent, elsősorban a csatornarodopszinokkal kapcsolatban: ezek ott szenzoros fotoreceptorokként szolgálnak az egysejtű zöldalgákban, szabályozva a fototaxist, azaz a fényre adott mozgást. Később (2005 után) ezt a fehérjét, mint eszközt használták fel „optikai távvezérlésre”, hozzákapcsolva ioncsatornához és ezzel fénykapuzottá téve azokat. Ezzel szemben a mi méréseink a béka-oocitákban természetes módon kifejeződő fehérjékre irányul. Célunk az előkísérleteink során tapasztalt, fénnyel való megvilágításra adott áramválaszok szisztematikus jellemzése, illetve a fény által létrehozott mechanizmus felfedése volt.Kísérleteinket két-elektródás voltage clamp technikával végeztük, agar-hídak alkalmazásával biztosítva a stabil elektromos referenciát és minimalizálva a folyadék-cseréből származó eletromos potenciálváltozási műtermékeket.A mérések során többféle fürdőoldatot alkalmaztunk, különböző ionkoncentrációkkal, annak vizsgálatára, hogy az ionösszetétel és az elektrokémiai grádiensek módosítása hogyan befolyásolja a fény által kiváltott áramokat. A kék fénnyel (≈450 nm) történő megvilágítás rendre jól elkülöníthető és a megvilágítás kikapcsolása után lecsengő áramválaszokat eredményezett. Ezek a fényindukált áramok minden vizsgált oldat esetében megjelentek. Eredményeink egyik kulcsmomentumát az jelentette, hogy az oldatösszetétel megváltoztatása – különösen a domináns kation cseréje Na⁺ és K⁺ között – nem eredményezte a reverzálpotenciál klasszikus módon értelmezhető eltolódását. Membárnpotenciáltól függően mind kifelé folyó, mind befelé folyó ionáramok voltak mérhetőek.Kutatásunk hozzájárul a Xenopus oocyták endogén fényérzékeny elektrofiziológiai jelenségeinek megértéséhez, amely során akár fénykapuzott ioncsatornák felfedezéséhez is eljuthatunk. Továbbá rávilágít arra is, hogy a fényhatások figyelembevétele fontos lehet minden olyan kísérletben, ahol az oocytákat erős optikai megvilágításnak tesszük ki.

Témavezető: Dr. Papp Ferenc

Bevezetés: A vörösvérsejtek deformabilitását a sejtek alakja, mérete, intracelluláris viszkozitása és a membrán viszkoelasztikus tulajdonságai mellett az őket körülvevő közeg ozmolaritása is jelentősen befolyásolja. Korábbi vizsgálataink alapján az ember és több laboratóriumi állatfaj összehasonlításában az ozmotikus gradiens deformabilitás paraméterei jelentősen különbségeket mutatnak. Jelen tanulmányban azt vizsgáltuk, hogy a glükóz koncentrációja milyen hatással van a vörösvérsejtek ozmotikus gradiens deformabilitására, s hogy mutatkozik-e ebben is különbség az ember és egyes kísérleti állatfajok között. Módszerek: Hat Topigs Norswin sertésből (19,7±0,8 kg), 10 Wistar patkányból (289,4±18 g) (engedély ny. szám: 20/2022/DEMÁB), valamint tíz önkéntestől (etikai engedély szám: DE-RKEB 3625-2012) vénás vérmintát vettünk. Az ozmotikus gradiens deformabilitás (osmoscan) mérésekhez (LoRRca MaxSis Osmoscan) négy glükóz-koncentrációjú (0, 6,25, 12,5 és 25 mmol/l) polyvinyl-pyrrolidone (PVP) oldat-sorozatot készítettünk. Így állandó nyírófeszültség alkalmazásával (30 Pa), ~50–500 mOsmol/l ozmolaritás grádiens mellett mért elongatiós index (EI) értékeket határoztunk meg mind a négyféle glükóz koncentráció esetén.Eredmények: Az EI-ozmolaritás görbék vizsgálata során a fajok közötti különbségeken túl a glükózkoncentráció növekedésére eltérő változásokat figyeltünk meg. A minimális EI értékek a humán és sertés mintákban szignifikánsan alacsonyabbak volt a patkányok értékeihez képest (p<0,001). A maximális EI esetében a humán vérmintákban a 0 mmol/l-es koncentrációhoz képest kimutatható, szignifikáns eltérést tapasztaltunk. A hiperozmoláris EI értékeknél a patkány (p<0,007; p<0,001; p<0,034) és a sertés (p<0,009; p<0,001; p<0,002) eredményei szignifikánsan magasabbak voltak az emberhez képest. A görbe alatti terület emberben minden vizsgált koncentrációnál jelentősen csökkent (p<0,001). Összességében az EI-ozmolaritás görbék a humán vérmintákban jellemzően lefelé enyhén jobbra, a patkányban balra lefelé, míg sertésben balra tolódtak el. Következtetés: A humán és a vizsgált laboratóriumi állatfajok tekintetében a glükóz koncentráció emelkedése eltérő mértékben rontotta a vörösvérsejtek ozmotikus grádiens deformabilitását. A legérzékenyebbek az ember és a sertés, míg a legellenállóbbak a patkány vörösvérsejtjei voltak.

Témavezető: Dr. Deák Ádám és Záhorszki Sándor Richárd