Mitochondrial calcium signaling in the brain and its modulation by neurotropic viruses

Investigation of copper-induced intestinal damage and proteome alterations in Takifugu rubripes: Potential health risks and environmental toxicology detection

Copper is one of the predominant water pollutants. Excessive exposure to copper can cause harm to animal health, affecting the central nervous system and causing blood abnormalities. Cuproptosis is a novel form of cell death that differs from previous programmed cell death methods. However, the impact of copper on the intestines remains unclear. Therefore, we investigated the effects of different concentrations of copper exposure on the intestinal proteome of Takifugu rubripes (T. rubripes). Relevant biomarkers were used to detect cuproptosis. We revealed the crosstalk relationship between cuproptosis and self-rescue at different concentrations, and discussed the feasibility of using potential cuproptosis indicators as anti-infection factors. We observed intestinal damage in the three copper exposure groups, especially in T. rubripes treated with 100 and 500 μg/L copper, with shedding and breakage of intestinal villus and fuzzy and loose structure of intestinal mucosa. The presence of copper stress not only causes cuproptosis but also oxidative damage caused by reactive oxygen species (ROS). The results of quantitative proteomics by TMT showed that compared to the 50 and 100 μg/L copper exposure groups, the expression of glutaminase, pyruvate kinase, and skin mucus lectin in the 500 μg/L group was significantly increased. The positive mediators COX5A and CTNNB1, as well as the negative mediators CD4 and FDXR, were found to be differentially expressed. Using the protein expression trends of cuproptosis indicator factors FDX1 and DLAT to indicate the concentration of copper ions in the environment. In addition, we found a new effect of promoting ferroptosis: providing additional copper ions can activate the phenomenon of ferroptosis. Our results expand our understanding of the potential health risks of copper in T. rubripes. At the same time, it is of great significance for the process of copper poisoning and the development of new environmental toxicology detection reagents.

Potential role of lncRNA in impairing cellular properties of human neural progenitor cells following exposure to Zika virus E protein

Zika virus (ZIKV) infection during the first trimester of the pregnancy may lead to Congenital zika syndrome in the neonates. The viral infection hampers foetal brain development and causes microcephaly. Human neural progenitor cells (hNPCs) play an important role in brain development, however they are highly susceptible to ZIKV infection. In this study, we elucidated the molecular mechanisms that lead to cellular alterations in hNPCs due to ZIKV E-protein. We investigated proliferation, differentiation, migration and inflammation in hNPCs, which may lead to microcephaly. In our study, we found that ZIKV E-protein causes cell cycle arrest, decrease in proliferation and increase in mitotic length of the dividing hNPCs. We observed CyclinD1 and upstream molecules (p21 and p53) of the pathway are dysregulated, and intracellular calcium at basal level as well as upon ATP stimulation were reduced following over expression of ZIKV E-protein. ZIKV E-protein transfected hNPCs exhibited pre-mature differentiation with pro-neural genes upregulated. Furthermore, ZIKV E-protein disrupted migrational properties of hNPCs and caused elevated levels of inflammatory chemokines and cytokines. To gain insights into molecular mechanisms of these effects on hNPCs, we explored the possible involvement of long non coding RNAs in ZIKV neuropathogenesis. We have shortlisted lncRNAs associated with differentially expressed genes from publicly available transcriptomic data and found some of those lncRNAs are differentially expressed upon E-protein transfection of hNPCs. Gene ontology analysis suggest these lncRNAs play an important role in regulation of viral life cycle, host's defence response and cell proliferation.

A combined X-ray fluorescence and infrared microspectroscopy study for new insights into elemental-biomolecular obesity-induced changes in rat brain structures

The objective of our research was to determine the brain changes at the molecular and elemental levels typical of early-stage obesity. Therefore a combined approach using Fourier transform infrared micro-spectroscopy (FTIR-MS) and synchrotron radiation induced X-ray fluorescence (SRXRF) was introduced to evaluate some brain macromolecular and elemental parameters in high-calorie diet (HCD)- induced obese rats (OB, n = 6) and in their lean counterparts (L, n = 6). A HCD was found to alter the lipid- and protein- related structure and elemental composition of the certain brain areas important for energy homeostasis. The increased lipid unsaturation in the frontal cortex and ventral tegmental area, the increased fatty acyl chain length in the lateral hypothalamus and substantia nigra as well as the decreased both protein α helix to protein β- sheet ratio and the percentage fraction of β-turns and β-sheets in the nucleus accumbens were revealed in the OB group reflecting obesity-related brain biomolecular aberrations. In addition, the certain brain elements including P, K and Ca were found to differentiate the lean and obese groups at the best extent. We can conclude that HCD-induced obesity triggers lipid- and protein- related structural changes as well as elemental redistribution within various brain structures important for energy homeostasis. In addition, an approach applying combined X-ray and infrared spectroscopy was shown to be a reliable tool for identifying elemental-biomolecular rat brain changes for better understanding the interplay between the chemical and structural processes involved in appetite control.

In vivo investigation of mitochondria in lateral line afferent neurons and hair cells

To process sensory stimuli, intense energy demands are placed on hair cells and primary afferents. Hair cells must both mechanotransduce and maintain pools of synaptic vesicles for neurotransmission. Furthermore, both hair cells and afferent neurons must continually maintain a polarized membrane to propagate sensory information. These processes are energy demanding and therefore both cell types are critically reliant on mitochondrial health and function for their activity and maintenance. Based on these demands, it is not surprising that deficits in mitochondrial health can negatively impact the auditory and vestibular systems. In this review, we reflect on how mitochondrial function and dysfunction are implicated in hair cell-mediated sensory system biology. Specifically, we focus on live imaging approaches that have been applied to study mitochondria using the zebrafish lateral-line system. We highlight the fluorescent dyes and genetically encoded biosensors that have been used to study mitochondria in lateral-line hair cells and afferent neurons. We then describe the impact this in vivo work has had on the field of mitochondrial biology as well as the relationship between mitochondria and sensory system development, function, and survival. Finally, we delineate the areas in need of further exploration. This includes in vivo analyses of mitochondrial dynamics and biogenesis, which will round out our understanding of mitochondrial biology in this sensitive sensory system.

COVID-19-induced neurological symptoms: focus on the role of metal ions

Neurological symptoms are prevalent in both the acute and post-acute phases of coronavirus disease 2019 (COVID-19), and they are becoming a major concern for the prognosis of COVID-19 patients. Accumulation evidence has suggested that metal ion disorders occur in the central nervous system (CNS) of COVID-19 patients. Metal ions participate in the development, metabolism, redox and neurotransmitter transmission in the CNS and are tightly regulated by metal ion channels. COVID-19 infection causes neurological metal disorders and metal ion channels abnormal switching, subsequently resulting in neuroinflammation, oxidative stress, excitotoxicity, neuronal cell death, and eventually eliciting a series of COVID-19-induced neurological symptoms. Therefore, metal homeostasis-related signaling pathways are emerging as promising therapeutic targets for mitigating COVID-19-induced neurological symptoms. This review provides a summary for the latest advances in research related to the physiological and pathophysiological functions of metal ions and metal ion channels, as well as their role in COVID-19-induced neurological symptoms. In addition, currently available modulators of metal ions and their channels are also discussed. Collectively, the current work offers a few recommendations according to published reports and in-depth reflections to ameliorate COVID-19-induced neurological symptoms. Further studies need to focus on the crosstalk and interactions between different metal ions and their channels. Simultaneous pharmacological intervention of two or more metal signaling pathway disorders may provide clinical advantages in treating COVID-19-induced neurological symptoms.

Exogenous Players in Mitochondria-Related CNS Disorders: Viral Pathogens and Unbalanced Microbiota in the Gut-Brain Axis

Billions of years of co-evolution has made mitochondria central to the eukaryotic cell and organism life playing the role of cellular power plants, as indeed they are involved in most, if not all, important regulatory pathways. Neurological disorders depending on impaired mitochondrial function or homeostasis can be caused by the misregulation of "endogenous players", such as nuclear or cytoplasmic regulators, which have been treated elsewhere. In this review, we focus on how exogenous agents, i.e., viral pathogens, or unbalanced microbiota in the gut-brain axis can also endanger mitochondrial dynamics in the central nervous system (CNS). Neurotropic viruses such as Herpes, Rabies, West-Nile, and Polioviruses seem to hijack neuronal transport networks, commandeering the proteins that mitochondria typically use to move along neurites. However, several neurological complications are also associated to infections by pandemic viruses, such as Influenza A virus and SARS-CoV-2 coronavirus, representing a relevant risk associated to seasonal flu, coronavirus disease-19 (COVID-19) and "Long-COVID". Emerging evidence is depicting the gut microbiota as a source of signals, transmitted via sensory neurons innervating the gut, able to influence brain structure and function, including cognitive functions. Therefore, the direct connection between intestinal microbiota and mitochondrial functions might concur with the onset, progression, and severity of CNS diseases.

Dysregulation of host cell calcium signaling during viral infections: Emerging paradigm with high clinical relevance

Viral infections are one of the leading causes of human illness. Viruses take over host cell signaling cascades for their replication and infection. Calcium (Ca2+) is a versatile and ubiquitous second messenger that modulates plethora of cellular functions. In last two decades, a critical role of host cell Ca2+ signaling in modulating viral infections has emerged. Furthermore, recent literature clearly implicates a vital role for the organellar Ca2+ dynamics (influx and efflux across organelles) in regulating virus entry, replication and severity of the infection. Therefore, it is not surprising that a number of viral infections including current SARS-CoV-2 driven COVID-19 pandemic are associated with dysregulated Ca2+ homeostasis. The focus of this review is to first discuss the role of host cell Ca2+ signaling in viral entry, replication and egress. We further deliberate on emerging literature demonstrating hijacking of the host cell Ca2+ dynamics by viruses. In particular, a variety of viruses including SARS-CoV-2 modulate lysosomal and cytosolic Ca2+ signaling for host cell entry and replication. Moreover, we delve into the recent studies, which have demonstrated the potential of several FDA-approved drugs targeting Ca2+ handling machinery in inhibiting viral infections. Importantly, we discuss the prospective of targeting intracellular Ca2+ signaling for better management and treatment of viral pathogenesis including COVID-19. Finally, we highlight the key outstanding questions in the field that demand critical and timely attention.