Press-room / Digest

Multiple paralogs of foxg1, the regulator of forebrain development, in lampreys and sturgeons: the legacy of genomic duplications in the early evolution of vertebrates
The foxg1 is known as one of the key regulators of the early development of the forebrain and related sensory organs. Employees of the Laboratory of Molecular Basis of Embryogenesis of the Institute of Bioorganic Chemistry, Russian Academy of Sciences, were the first to identify multiple foxg1 paralogs in lampreys and sturgeons, as archaic representatives of two branches of vertebrates - jawless and gnathostomes. A phylogenetic analysis of vertebrate Foxg1 proteins was carried out, and the expression patterns of foxg1 paralogues in river lamprey and sterlet were studied. The timing of duplication of foxg1 paralogues in the evolution of agnathans and gnathostomes was estimated. As a result, no reliable pairwise orthology of the foxg1 genes was identified in agnathans and gnathostomes. At the same time, it was shown that the phylogeny of foxg1 paralogs in sturgeons corresponds to the model of ancestral duplication followed by asynchronous rediploidization and indicates a genomic duplication that occurred at the level of the common ancestor of sturgeons. The results are published in Frontiers in Cell and Developmental Biology. Learn more

Hydrogen peroxide is not generated intracellularly in human neural spheroids during ischemia-reperfusion
Reactive oxygen species (ROS) are considered a primary source of damage during an ischemic stroke. Studies on this subject are usually performed on either cell culture or animal models, which can make it difficult to translate the results to humans. Currently, 3D neurospheroids derived from induced pluripotent stem cells (iPSCs) are proposed as an optimal alternative for modeling disease conditions. Researchers from the IBCh RAS and other Russian institutions report live imaging of hydrogen peroxide dynamics during the acute phase of hypoxia and reperfusion in human iPSC-derived neural spheroids, stably expressing fluorescent biosensor HyPer7. Contrary to expectations, they demonstrated the absence of ROS overproduction during the ischemia-reperfusion experiment. These results raise concerns about the applicability of such ischemia-reperfusion models due to the lack of a hallmark ROS signature of ischemic stroke. The results are published in Free Radical Biology and Medicine. Learn more

Age-dependent astrocytic atrophy and mitochondrial malfunction in human neocortex
Scientists from the IBCh RAS in collaboration with colleagues from other institutes have delved into the intricate cellular changes occurring in the brains of aging adults. The results of the study challenges existing paradigms by uncovering distinct responses to aging in astrocytes and neurons. Key findings include a significant decrease in the amount of reduced mitochondrial cytochromes in astrocytes, signaling potential mitochondrial dysfunction linked to aging. Notably, this phenomenon was not observed in neurons, highlighting cell-specific nuances in the aging process. The findings pave the way for a more nuanced understanding of the aging process, considering cell-type-specific responses within the brain active milieu. The results are published in Nature Communications. Learn more

A non-canonical RNAi pathway induced by externally applied virus-specific dsRNA in plants
The external application of dsRNAh has recently been developed as a new approach for crop protection. It is assumed that the mechanism of dsRNA-mediated antivirus RNA defence is similar to that of natural RNA interference (RNAi). There is, however, no direct evidence to support this idea. Scientists from the IBCh RAS in collaboration with colleagues from JHI (UK) we carried out the analysis of small RNAs (sRNA) as hallmarks of RNAi induced by potato virus Y (PVY). In contrast to PVY-induced production of discrete 21 and 22 nt sRNA species, the externally administered PVY dsRNA led to generation of a non-canonical pool of sRNAs, which were present as ladders of ~18-30 nt in length; suggestive of an unexpected sRNA biogenesis. These findings may have significant implications for further developments in dsRNA-mediated crop protection. The results are published in the International Journal of Molecular Sciences. Learn more

Redox differences between neonatal and adult cardiomyocytes under hypoxia
A team of scientists from the IBCh RAS, Lomonosov Moscow State University and other Russian institutes studied the differences in the redox state of neonatal and adult rat cardiomyocytes under hypoxic conditions. Using the highly sensitive HyPer7 biosensor, authors found that hypoxia causes an increase in H2O2 production in adult cardiomyocytes, while neonatal cells, on the contrary, experience a decrease in basal H2O2 levels under the same conditions. This finding correlates with other data obtained by the authors using Raman microspectroscopy, which demonstrate a marked difference in the properties of the mitochondrial electron transport chain of adult and neonatal cells. In particular, in adult cardiomyocytes, hypoxia causes the significant increase in the respiratory chain loading with electrons, while in neonatal cells this effect is not observed. The work was published in Free Radical Biology and Medicine journal. Learn more