Does conserved domain SOD1 mutation has any role in ALS severity and therapeutic outcome?

Evolutionary insights into adaptation of hemocyanins from deep-sea hydrothermal vent shrimps

Deep-sea hydrothermal vent shrimps inhabit environments with low oxygen levels and may even be exposed to hypoxic conditions. In response, their respiratory pigment, hemocyanin (Hc) may undergo molecular adaptations to enable them to survive in such extreme ecosystems. Therefore, we sampled four Alvinocarididae species from hydrothermal vents in the northern Central Indian Ridge and two types of Hc genes (α and γ) were observed. Employing the branch model, we detected positive selection for the deep-sea hydrothermal vent lineage, including 11 Decapoda species. Furthermore, using the branch-site model, we identified a putative mutant residue (Leu226, Ser377, and Ile390) close to the active site of Hc. Moreover, our results suggested potential molecular docking between two α-type Hc proteins. Thus, this study provides valuable and novel perspectives on the functional significance of the Hc gene in deep-sea hydrothermal vent shrimps, laying the foundation for future investigations in this intriguing area of research.

Amino acid substitutions in specific proteins correlate with farnesol unresponsiveness in Candida albicans

BACKGROUND

The quorum-sensing molecule farnesol, in opportunistic yeast Candida albicans, modulates its dimorphic switch between yeast and hyphal forms, and biofilm formation. Although there is an increasing interest in farnesol as a potential antifungal drug, the molecular mechanism by which C. albicans responds to this molecule is still not fully understood.

RESULTS

A comparative genomic analysis between C. albicans strains that are naturally unresponsive to 30 µM of farnesol on TYE plates at 37 °C versus responsive strains uncovered new molecular determinants involved in the response to farnesol. While no signature gene was identified, amino acid changes in specific proteins were shown to correlate with the unresponsiveness to farnesol, particularly with substitutions in proteins known to be involved in the farnesol response. Although amino acid changes occur primarily in disordered regions of proteins, some amino acid changes were also found in known domains. Finally, the genomic investigation of intermediate-response strains showed that the non-response to farnesol occurs gradually following the successive accumulation of amino acid changes at specific positions.

CONCLUSION

It is known that large genomic changes, such as recombinations and gene flow (losses and gains), can cause major phenotypic changes in pathogens. However, it is still not well known or documented how more subtle changes, such as amino acid substitutions, play a role in the adaptation of pathogens. The present study shows that amino acid changes can modulate C. albicans yeast's response to farnesol. This study also improves our understanding of the network of proteins involved in the response to farnesol, and of the involvement of amino acid substitutions in cellular behavior.

Spatiotemporal evolution of pyroptosis and canonical inflammasome pathway in hSOD1G93A ALS mouse model

Background

Evidences indicate that inflammasome compounds participate in amyotrophic lateral sclerosis (ALS), a fatal progressive motoneuron degenerative disease. Researchers have observed the expressions of nucleotide oligomerization domain (NOD)-like receptor protein 3 (NLRP3) related inflammasome components in specific regions of the central nervous system in different ALS models, but the cellular spatiotemporal evolution of this canonical inflammasome pathway and pyroptosis during ALS progression are unclear.

Methods

The spinal cords of hSOD1^G93A mice (ALS mice) and age-matched littermates (CON mice) were dissected at pre-symptomatic stage (60 d), early- symptomatic stage (95 d), symptomatic stage (108 d) and late-symptomatic stage (122 d) of the disease. By using Nissl staining, double immunofluorescence labelling, qRT-PCR or western blot, we detected morphology change and the expression, cellular location of GSDMD, NLRP3, caspase-1 and IL-1β in the ventral horn of lumbar spinal cords over the course of disease.

Results

Neural morphology changes and GSDMD⁺/NeuN⁺ double positive cells were observed in ventral horn from ALS mice even at 60 d of age, even though there were no changes of GSDMD mRNA and protein expressions at this stage compared with CON mice. With disease progression, compared with age-matched CON mice, increased expressions of GSDMD, NLRP3, activated caspase-1 and IL-1β were detected. Double immunofluorescence labeling revealed that NLRP3, caspase-1, IL-1β positive signals mainly localized in ventral horn neurons at pre- and early-symptomatic stages. From symptomatic stage to late-symptomatic stage, robust positive signals were co-expressed in reactive astrocytes and microglia.

Conclusions

Early activation of the canonical NLRP3 inflammasome induced pyroptosis in ventral horn neurons, which may participate in motor neuron degeneration and initiate neuroinflammatory processes during ALS progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12868-022-00733-9.