Ischemic heart disease is the leading cause of mortality in developed countries. It is, therefore, not surprising that both experimental and clinical cardiologists have been focused on effective protection of the heart against ischemia/reperfusion (I/R) injury. It is widely accepted that mitochondrial dysfunction, mainly mitochondrial permeability transition pore (mPTP) opening, plays a major role in cardiac I/R injury. Adaptation to chronic hypoxia is a natural stimulus conferring a long-lasting cardioprotection against I/R. Its cardioprotective effects are associated with stabilization of hypoxia-inducible factor 1alpha (HIF-1alpha). The aim of the present study is, therefore, to determine whether HIF-1alpha stabilization is the key mechanism increasing myocardial tolerance to I/R injury and to analyze the effect of genetically and functionally modified HIF-1alpha levels on mitochondrial function and mPTP opening during I/R injury. These results should contribute to the clarification of mechanisms participating in the protection of the ischemic heart.

Ischemická choroba srdeční je hlavní příčinou morbidity a mortality ve vyspělých zemích. Je proto pochopitelné, že zájem experimentálních a klinických kardiologů se v průběhu uplynulých 45 let soustředil na studium možného snížení rozsahu ischemického postižení srdečního svalu. Bylo zjištěno, že klíčovou roli v určení rozsahu ischemicko/reperfuzního (I/R) poškození hraje porucha funkce mitochondrií, zvláště pak otevření mitochondriálního póru (mPTP). Adaptace na chronickou hypoxii dlouhodobě významně zvyšuje odolnost srdečního svalu k I/R poškození; tento protektivní efekt je doprovázen stabilizací hypoxií-indukovaného faktoru 1alfa (HIF-1alfa). Cílem projektu je proto zjistit, zda stabilizace HIF-1alfa je klíčovým mechanismem zvýšené odolnosti srdce k I/R poškození a analyzovat vliv geneticky a funkčně změněných hladin HIF-1alfa na funkci mitochondrií, především pak na pravděpodobnost otevření mPTP póru při I/R poškození. Očekávané výsledky by měly přispět k objasnění mechanismů, které se uplatňují v protekci ischemického myokardu.

• Klíčová slova
• infarkt myokardu, kardioprotekce, myocardial infarction, cardioprotection, Mitochondrie, Mitochondria, chronická hypoxie, hypoxií-indukovaný faktor 1alfa, chronic hypoxia, hypoxia-inducible factor 1alpha,

• NLK Publikační typ
• závěrečné zprávy o řešení grantu AZV MZ ČR

Transcription factors belonging to the basic helix-loop-helix (bHLH) family are key regulators of cell fate specification and differentiation during development. Their dysregulation is implicated not only in developmental abnormalities but also in various adult diseases and cancers. Recently, the abilities of bHLH factors have been exploited in reprogramming strategies for cell replacement therapy. One such factor is NEUROD1, which has been associated with the reprogramming of the epigenetic landscape and potentially possessing pioneer factor abilities, initiating neuronal developmental programs, and enforcing pancreatic endocrine differentiation. The review aims to consolidate current knowledge on NEUROD1's multifaceted roles and mechanistic pathways in human and mouse cell differentiation and reprogramming, exploring NEUROD1 roles in guiding the development and reprogramming of neuroendocrine cell lineages. The review focuses on NEUROD1's molecular mechanisms, its interactions with other transcription factors, its role as a pioneer factor in chromatin remodeling, and its potential in cell reprogramming. We also show a differential potential of NEUROD1 in differentiation of neurons and pancreatic endocrine cells, highlighting its therapeutic potential and the necessity for further research to fully understand and utilize its capabilities.

• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

AIM: The transcriptional factor HIF-1α is recognized for its contribution to cardioprotection against acute ischemia/reperfusion injury. Adaptation to chronic hypoxia (CH) is known to stabilize HIF-1α and increase myocardial ischemic tolerance. However, the precise role of HIF-1α in mediating the protective effect remains incompletely understood. METHODS: Male wild-type (WT) mice and mice with partial Hif1a deficiency (hif1a +/-) were exposed to CH for 4 weeks, while their respective controls were kept under normoxic conditions. Subsequently, their isolated perfused hearts were subjected to ischemia/reperfusion to determine infarct size, while RNA-sequencing of isolated cardiomyocytes was performed. Mitochondrial respiration was measured to evaluate mitochondrial function, and western blots were performed to assess mitophagy. RESULTS: We demonstrated enhanced ischemic tolerance in WT mice induced by adaptation to CH compared with their normoxic controls and chronically hypoxic hif1a +/- mice. Through cardiomyocyte bulk mRNA sequencing analysis, we unveiled significant reprogramming of cardiomyocytes induced by CH emphasizing mitochondrial processes. CH reduced mitochondrial content and respiration and altered mitochondrial ultrastructure. Notably, the reduced mitochondrial content correlated with enhanced autophagosome formation exclusively in chronically hypoxic WT mice, supported by an increase in the LC3-II/LC3-I ratio, expression of PINK1, and degradation of SQSTM1/p62. Furthermore, pretreatment with the mitochondrial division inhibitor (mdivi-1) abolished the infarct size-limiting effect of CH in WT mice, highlighting the key role of mitophagy in CH-induced cardioprotection. CONCLUSION: These findings provide new insights into the contribution of HIF-1α to cardiomyocyte survival during acute ischemia/reperfusion injury by activating the selective autophagy pathway.

• MeSH
• faktor 1 indukovatelný hypoxií - podjednotka alfa * metabolismus   genetika   MeSH
• fyziologická adaptace fyziologie   MeSH
• hypoxie * metabolismus   MeSH
• infarkt myokardu * metabolismus   patologie   genetika   MeSH
• kardiomyocyty metabolismus   patologie   MeSH
• mitofagie * fyziologie   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Auditory processing in mammals begins in the peripheral inner ear and extends to the auditory cortex. Sound is transduced from mechanical stimuli into electrochemical signals of hair cells, which relay auditory information via the primary auditory neurons to cochlear nuclei. Information is subsequently processed in the superior olivary complex, lateral lemniscus, and inferior colliculus and projects to the auditory cortex via the medial geniculate body in the thalamus. Recent advances have provided valuable insights into the development and functioning of auditory structures, complementing our understanding of the physiological mechanisms underlying auditory processing. This comprehensive review explores the genetic mechanisms required for auditory system development from the peripheral cochlea to the auditory cortex. We highlight transcription factors and other genes with key recurring and interacting roles in guiding auditory system development and organization. Understanding these gene regulatory networks holds promise for developing novel therapeutic strategies for hearing disorders, benefiting millions globally.

• MeSH
• lidé MeSH
• mozek metabolismus   růst a vývoj   MeSH
• sluch * fyziologie   MeSH
• sluchová dráha * fyziologie   MeSH
• sluchové korové centrum metabolismus   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

INTRODUCTION: Maternal diabetes is a recognized risk factor for both short-term and long-term complications in offspring. Beyond the direct teratogenicity of maternal diabetes, the intrauterine environment can influence the offspring's cardiovascular health. Abnormalities in the cardiac sympathetic system are implicated in conditions such as sudden infant death syndrome, cardiac arrhythmic death, heart failure, and certain congenital heart defects in children from diabetic pregnancies. However, the mechanisms by which maternal diabetes affects the development of the cardiac sympathetic system and, consequently, heightens health risks and predisposes to cardiovascular disease remain poorly understood. METHODS AND RESULTS: In the mouse model, we performed a comprehensive analysis of the combined impact of a Hif1a-deficient sympathetic system and the maternal diabetes environment on both heart development and the formation of the cardiac sympathetic system. The synergic negative effect of exposure to maternal diabetes and Hif1a deficiency resulted in the most pronounced deficit in cardiac sympathetic innervation and the development of the adrenal medulla. Abnormalities in the cardiac sympathetic system were accompanied by a smaller heart, reduced ventricular wall thickness, and dilated subepicardial veins and coronary arteries in the myocardium, along with anomalies in the branching and connections of the main coronary arteries. Transcriptional profiling by RNA sequencing (RNA-seq) revealed significant transcriptome changes in Hif1a-deficient sympathetic neurons, primarily associated with cell cycle regulation, proliferation, and mitosis, explaining the shrinkage of the sympathetic neuron population. DISCUSSION: Our data demonstrate that a failure to adequately activate the HIF-1α regulatory pathway, particularly in the context of maternal diabetes, may contribute to abnormalities in the cardiac sympathetic system. In conclusion, our findings indicate that the interplay between deficiencies in the cardiac sympathetic system and subtle structural alternations in the vasculature, microvasculature, and myocardium during heart development not only increases the risk of cardiovascular disease but also diminishes the adaptability to the stress associated with the transition to extrauterine life, thus increasing the risk of neonatal death.

• MeSH
• dítě MeSH
• faktor 1 indukovatelný hypoxií - podjednotka alfa metabolismus   MeSH
• gestační diabetes * metabolismus   MeSH
• kardiovaskulární nemoci * metabolismus   MeSH
• lidé MeSH
• myokard metabolismus   MeSH
• myši MeSH
• novorozenec MeSH
• srdce MeSH
• srdeční selhání * MeSH
• těhotenství MeSH
• zvířata MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• myši MeSH
• novorozenec MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

A gene cadre orchestrates the normal development of sensory and non-sensory cells in the inner ear, segregating the cochlea with a distinct tonotopic sound frequency map, similar brain projection, and five vestibular end-organs. However, the role of genes driving the ear development is largely unknown. Here, we show double deletion of the Iroquois homeobox 3 and 5 transcription factors (Irx3/5 DKO) leads to the fusion of the saccule and the cochlear base. The overlying otoconia and tectorial membranes are absent in the Irx3/5 DKO inner ear, and the primary auditory neurons project fibers to both the saccule and cochlear hair cells. The central neuronal projections from the cochlear apex-base contour are not fully segregated into a dorsal and ventral innervation in the Irx3/5 DKO cochlear nucleus, obliterating the characteristic tonotopic auditory map. Additionally, Irx3/5 deletion reveals a pronounced cochlear-apex-vestibular "vestibular-cochlear" nerve (VCN) bilateral connection that is less noticeable in wild-type control mice. Moreover, the incomplete segregation of apex and base projections that expands fibers to connect with vestibular nuclei. The results suggest the mammalian cochlear apex is a derived lagena reminiscent of sarcopterygians. Thus, Irx3 and 5 are potential evolutionary branch-point genes necessary for balance-sound segregation, which fused into a saccule-cochlea organization.

• MeSH
• homeodoménové proteiny * genetika   metabolismus   MeSH
• kochlea * fyziologie   MeSH
• myši knockoutované * MeSH
• myši MeSH
• sakulus a utrikulus * fyziologie   MeSH
• sluchová dráha fyziologie   MeSH
• transkripční faktory * genetika   metabolismus   nedostatek   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

NEUROD1 is a transcription factor that helps maintain a mature phenotype of pancreatic β cells. Disruption of Neurod1 during pancreatic development causes severe neonatal diabetes; however, the exact role of NEUROD1 in the differentiation programs of endocrine cells is unknown. Here, we report a crucial role of the NEUROD1 regulatory network in endocrine lineage commitment and differentiation. Mechanistically, transcriptome and chromatin landscape analyses demonstrate that Neurod1 inactivation triggers a downregulation of endocrine differentiation transcription factors and upregulation of non-endocrine genes within the Neurod1-deficient endocrine cell population, disturbing endocrine identity acquisition. Neurod1 deficiency altered the H3K27me3 histone modification pattern in promoter regions of differentially expressed genes, which resulted in gene regulatory network changes in the differentiation pathway of endocrine cells, compromising endocrine cell potential, differentiation, and functional properties.

• MeSH
• aktivace transkripce MeSH
• beta-buňky * MeSH
• buněčná diferenciace genetika   MeSH
• endokrinní buňky * MeSH
• transkripční faktory MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The development of the central auditory system, including the auditory cortex and other areas involved in processing sound, is shaped by genetic and environmental factors, enabling infants to learn how to speak. Before explaining hearing in humans, a short overview of auditory dysfunction is provided. Environmental factors such as exposure to sound and language can impact the development and function of the auditory system sound processing, including discerning in speech perception, singing, and language processing. Infants can hear before birth, and sound exposure sculpts their developing auditory system structure and functions. Exposing infants to singing and speaking can support their auditory and language development. In aging humans, the hippocampus and auditory nuclear centers are affected by neurodegenerative diseases such as Alzheimer's, resulting in memory and auditory processing difficulties. As the disease progresses, overt auditory nuclear center damage occurs, leading to problems in processing auditory information. In conclusion, combined memory and auditory processing difficulties significantly impact people's ability to communicate and engage with their societal essence.

• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

BACKGROUND: An altered sympathetic nervous system is implicated in many cardiac pathologies, ranging from sudden infant death syndrome to common diseases of adulthood such as hypertension, myocardial ischemia, cardiac arrhythmias, myocardial infarction, and heart failure. Although the mechanisms responsible for disruption of this well-organized system are the subject of intensive investigations, the exact processes controlling the cardiac sympathetic nervous system are still not fully understood. A conditional knockout of the Hif1a gene was reported to affect the development of sympathetic ganglia and sympathetic innervation of the heart. This study characterized how the combination of HIF-1α deficiency and streptozotocin (STZ)-induced diabetes affects the cardiac sympathetic nervous system and heart function of adult animals. METHODS: Molecular characteristics of Hif1a deficient sympathetic neurons were identified by RNA sequencing. Diabetes was induced in Hif1a knockout and control mice by low doses of STZ treatment. Heart function was assessed by echocardiography. Mechanisms involved in adverse structural remodeling of the myocardium, i.e. advanced glycation end products, fibrosis, cell death, and inflammation, was assessed by immunohistological analyses. RESULTS: We demonstrated that the deletion of Hif1a alters the transcriptome of sympathetic neurons, and that diabetic mice with the Hif1a-deficient sympathetic system have significant systolic dysfunction, worsened cardiac sympathetic innervation, and structural remodeling of the myocardium. CONCLUSIONS: We provide evidence that the combination of diabetes and the Hif1a deficient sympathetic nervous system results in compromised cardiac performance and accelerated adverse myocardial remodeling, associated with the progression of diabetic cardiomyopathy.

• MeSH
• diabetická kardiomyopatie * genetika   MeSH
• experimentální diabetes mellitus * chemicky indukované   genetika   komplikace   MeSH
• myokard metabolismus   MeSH
• myši MeSH
• srdce inervace   MeSH
• sympatický nervový systém metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: Glucose homeostasis is dependent on functional pancreatic α and ß cells. The mechanisms underlying the generation and maturation of these endocrine cells remain unclear. RESULTS: We unravel the molecular mode of action of ISL1 in controlling α cell fate and the formation of functional ß cells in the pancreas. By combining transgenic mouse models, transcriptomic and epigenomic profiling, we uncover that elimination of Isl1 results in a diabetic phenotype with a complete loss of α cells, disrupted pancreatic islet architecture, downregulation of key ß-cell regulators and maturation markers of ß cells, and an enrichment in an intermediate endocrine progenitor transcriptomic profile. CONCLUSIONS: Mechanistically, apart from the altered transcriptome of pancreatic endocrine cells, Isl1 elimination results in altered silencing H3K27me3 histone modifications in the promoter regions of genes that are essential for endocrine cell differentiation. Our results thus show that ISL1 transcriptionally and epigenetically controls α cell fate competence, and ß cell maturation, suggesting that ISL1 is a critical component for generating functional α and ß cells.

• Publikační typ
• časopisecké články MeSH