Amyotrophic Lateral Sclerosis Mechanism: Insights from the Caenorhabditis elegans Models

Amyotrophic Lateral Sclerosis (ALS) is a debilitating neurodegenerative condition characterized by the progressive degeneration of motor neurons. Despite extensive research in various model animals, the cellular signal mechanisms of ALS remain elusive, impeding the development of efficacious treatments. Among these models, a well-characterized and diminutive organism, Caenorhabditis elegans (C. elegans), has emerged as a potent tool for investigating the molecular and cellular dimensions of ALS pathogenesis. This review summarizes the contributions of C. elegans models to our comprehension of ALS, emphasizing pivotal findings pertaining to genetics, protein aggregation, cellular pathways, and potential therapeutic strategies. We analyze both the merits and constraints of the C. elegans system in the realm of ALS research and point towards future investigations that could bridge the chasm between C. elegans foundational discoveries and clinical applications.

Novel Extraction Method for Combined Lipid and Metal Speciation From Caenorhabditis elegans With Focus on Iron Redox Status and Lipid Profiling

Parkinson´s disease progression is linked to iron redox status homeostasis via reactive oxygen species (ROS) formation, and lipids are the primary targets of ROS. The determination of iron redox status in vivo is challenging and requires specific extraction methods, which are so far tedious and very time-consuming. We demonstrated a novel, faster, and less laborious extraction method using the chelator ethylene glycol l-bis(β-aminoethyl ether)-N,N,N′,N′-tetra acetic acid (EGTA) as a stabilizing agent and synthetic quartz beads for homogenization under an argon atmosphere. Additionally, we combined the metal extraction with a well-established lipid extraction protocol using methyl-tert-butyl ether (MTBE) to avoid the problems of lipid precipitation in frozen samples and to determine lipid profiles and metal species from the same batch. The nonextractable matrix, such as the debris, is removed by centrifugation and digested to determine the total metal content of the sample as well. Lipid profiling using RP-LC–MS demonstrated high accordance of the modified extraction method to the reference method, and the organic solvent does not affect the iron redox status equilibrium. Furthermore, rigorous testing demonstrated the stability of the iron redox status equilibrium during the extraction process, secured by complexation, inert atmosphere, fast preparation, and immediately deep frozen extracts.

Computing Temporal Sequences Associated With Dynamic Patterns on the C. elegans Connectome

Understanding how the structural connectivity and spatial geometry of a network constrains the dynamics it is able to support is an active and open area of research. We simulated the plausible dynamics resulting from the known C. elegans connectome using a recent model and theoretical analysis that computes the dynamics of neurobiological networks by focusing on how local interactions among connected neurons give rise to the global dynamics in an emergent way. We studied the dynamics which resulted from stimulating a chemosensory neuron (ASEL) in a known feeding circuit, both in isolation and embedded in the full connectome. We show that contralateral motorneuron activations in ventral (VB) and dorsal (DB) classes of motorneurons emerged from the simulations, which are qualitatively similar to rhythmic motorneuron firing pattern associated with locomotion of the worm. One interpretation of these results is that there is an inherent—and we propose—purposeful structural wiring to the C. elegans connectome that has evolved to serve specific behavioral functions. To study network signaling pathways responsible for the dynamics we developed an analytic framework that constructs Temporal Sequences (TSeq), time-ordered walks of signals on graphs. We found that only 5% of TSeq are preserved between the isolated feeding network relative to its embedded counterpart. The remaining 95% of signaling pathways computed in the isolated network are not present in the embedded network. This suggests a cautionary note for computational studies of isolated neurobiological circuits and networks.

Ultrasonic-assisted extraction of polysaccharides from Auricularia auricula and effects of its acid hydrolysate on the biological function of Caenorhabditis elegans

The present study was designed to explore the in vivo-antioxidant capacity and the probable mechanism of AAPs-H, prepared from Auricularia auricula polysaccharides with the optimal extraction conditions by Box-Behnken design and acid hydrolysis, using Caenorhabditis elegans as a model organism. The effects of AAPs-H on the locomotion behavior, life span, antioxidant-related enzymes activities, and antioxidants levels in C. elegans were studied. Furthermore, the potentials of AAPs-H in up-regulating the expression of antioxidant-related genes in C. elegans, such as skn-1, sod-3 and sir-2.1, were also discussed. AAPs-H demonstrated a highly significant protective effect against the damage caused by paraquat, could significantly increase U-Turn frequency of worms (p < 0.01), extend their lifespan, enhance antioxidant systems including GR by 63.96% (p < 0.05), GSH-Px by 71.16% (p < 0.01), SOD by 78.65% (p < 0.01) and CAT by 98.52% (p < 0.01), increase the level of GSH by 28.12% (p < 0.05), and decrease the level of MDA by 39.29% (p < 0.01). The qRT-PCR results showed that AAPs-H could up regulate mRNA expression levels of skn-1, sod-1, sod-2, sod-3 and sir-2.1 in wild-type C. elegans (>1.6 fold) when treated with the concentration of 0.4 mg/mL (p < 0.05 or p < 0.01). Our studies provide evidence that AAPs-H improves antioxidant defense system, and up-regulation of oxidative stress related genes for prevention of stress damage in C. elegans.

The antioxidant capacity evaluation of polysaccharide hydrolyzates from pumpkin using Caenorhabditis elegans model

Our previous study has optimized the acid hydrolysis process of pumpkin polysaccharides (PPe) with scavenging ability based on central composite design. The aim of this study was to explore the in vivo-antioxidant ability of PPe and pumpkin polysaccharides acid-hydrolysis (PPe-S) using Caenorhabditis elegans. In composition analysis, the constituents of total sugar, protein, uronic acid, and sulfur groups in PPe-S were 87.03 ± 1.21%, 1.25 ± 0.78%, 37.61 ± 0.97%, and 0.14 ± 0.04%, respectively. Besides, results of antioxidant ability showed that PPe and PPe-S could reduce the oxidative stress (OS) induced by methyl viologen, extend lifespan of worms, and reduce reactive oxygen species (ROS) level under oxidative conditions significantly (p < .05). Furthermore, PPe and PPe-S could enhance the stress-resistance related antioxidant enzymes including catalase (CAT) and superoxide dismutase (SOD) significantly (p < .05). Moreover, the antioxidant effect of PPe-S was superior to PPe at the concentration of 4.0 mg/ml. In summary, this study demonstrated that the derived hydrolyzates from PPe had protective effects on the damage induced by the generation of intracellular free radical agents. PRACTICAL APPLICATIONS: OS plays an important role in the pathogenesis of metabolic diseases, including type 2 diabetes. It is widely acknowledged that diabetes and its complications pose a threat to human's health, and the number of people with diabetes will expand to 640 million in the 2040 year. Current studies have shown that all diabetes drugs have a kind of side effects. Fortunately, researchers have found and confirmed that plant-derived polysaccharide had a notable hypoglycemic effect via reducing the OS level in cell and tissue, and could decrease the diabetes symptoms as well. In this study, we proved that the polysaccharide derived from pumpkin could effectively ameliorate the OS level in C. elegans, including decreasing the damage of biofilm and ROS level. Therefore, our study shows that there is a high potential for pumpkin-derived polysaccharide and its hydrolyzates to be a bioactive component to prevent diabetes. In other words, this research can be applied to diabetes prevention and other diseases induced by OS.