Mir, D. A. | Search bioRxiv

bioRxiv2024

Roles of progranulin and FRamides in neural versus non-neural tissues on dietary restriction-related longevity and proteostasis in C. elegans

Dietary restriction (DR) mitigates loss of proteostasis associated with aging that underlies neurodegenerative conditions including Alzheimers disease and related dementias. Previously, we observed increased translational efficiency of certain FMRFamide-like neuropeptide (flp) genes and the neuroprotective growth factor progranulin gene prgn-1 under dietary restriction in C. elegans. Here, we tested the effects of flp-5, flp-14, flp-15 and pgrn-1 on lifespan and proteostasis under both standard and dietary restriction conditions. We also tested and distinguished function based on their expression in either neuronal or non-neuronal tissue. Lowering the expression of pgrn-1 and flp genes selectively in neural tissue showed no difference in survival under normal feeding conditions nor under DR in two out of three experiments performed. Reduced expression of flp-14 in non-neuronal tissue showed decreased lifespan that was not specific to DR. With respect to proteostasis, a genetic model of DR from mutation of the eat-2 gene that showed increased thermotolerance compared to fully fed wild type animals demonstrated no change in thermotolerance in response to knockdown of pgrn-1 or flp genes. Finally, we tested effects on motility in a neural-specific model of proteotoxicity and found that neuronal knockdown of pgrn-1 and flp genes improved motility in early life regardless of diet. However, knocking these genes down in non-neuronal tissue had variable results. RNAi targeting flp-14 increased motility by day seven of adulthood regardless of diet. Interestingly, non-neuronal RNAi of pgrn-1 decreased motility under standard feeding conditions while DR increased motility for this gene knockdown by day seven (early mid-life). Results show that pgrn-1, flp-5, flp-14, and flp-15 do not have major roles in diet-related changes in longevity or whole-body proteostasis. However, reduced expression of these genes in neurons increases motility early in life in a neural-specific model of proteotoxicity, whereas knockdown of non-neuronal expression mostly increases motility in mid-life under the same conditions.

molecular biology↗

bioRxiv2019

Proteomic analysis of Caenorhabditis elegans against S. Typhi toxic proteins

Background & AimsBacterial effector molecules are the crucial infectious agents and are sufficient to cause pathogenesis. In the present study, pathogenesis of S. Typhi toxic proteins on the model host Caenorhabditis elegans was investigated by exploring the host regulatory proteins during infection through quantitative proteomics approach. MethodsIn this regard, the host proteome was analysed using two-dimensional gel electrophoresis (2D-GE) and differentially regulated proteins were identified using MALDI TOF/TOF/MS analysis. Out of the 150 regulated proteins identified, 95 proteins were appeared to be downregulated while 55 were upregulated. Interaction network for regulated proteins was predicted using STRING tool. ResultsMost of the downregulated proteins were found to be involved in muscle contraction, locomotion, energy hydrolysis, lipid synthesis, serine/threonine kinase activity, oxidoreductase activity and protein unfolding and upregulated proteins were found to be involved in oxidative stress pathways. Hence, cellular stress generated by S. Typhi proteome on the model host was determined using lipid peroxidation, oxidant and antioxidant assays. In addition to that the candidate proteins resulted from the host proteome analysis were validated by Western blotting and roles of several crucial molecular players were analyzed in vivo using wild type and mutant C. elegans. ConclusionsTo the best of our knowledge, this is the first study to report the protein regulation in host C. elegans during S. Typhi toxic proteins exposure which highlights the significance of p38 MAPK and JNK immune pathways. These results may provide new clues for future therapeutic approaches for curing bacterial toxin protein-mediated infections in a host system. SummaryWe have precipitated the toxin proteins of S.Typhi. To gain insight into the worms response to ingestion of toxin, a proteomic analysis was performed to monitor the changes in protein regulation. 150 differential regulated proteins were identified, amongst 95 and 55 proteins were found to be downregulated and upregulated, respectively. This is the first study that reported the global proteome changes in C. elegans against toxin. Our findings suggested involvement of several regulatory proteins that appear to play a role in various molecular functions in combating toxin-mediated microbial pathogenicity and/or host C. elegans immunity modulation. A proteomics approach using C. elegans can facilitate the understanding of how toxin can lead to intoxication, which pave a way for delineating how higher eukaryotes could evolve defenses to protect against bacterial toxin. Toxin infection nematode showed increased accumulation of proteins that respond to oxidative -stress, lipid metabolism, embryonic development, immune and inflammatory processes.

pathology↗