Structural characterization of life-extending Caenorhabditis elegans Lipid Binding Protein 8

FABP5-binding lipids regulate autophagy in differentiated SH-SY5Y cells

The motor features of Parkinson's disease result from loss of dopaminergic neurons in the substantia nigra with autophagy dysfunction being closely linked to this disease. While a large body of work focusing on protein effectors of autophagy has been reported, regulation of autophagy by lipids has garnered far less attention. Therefore, we sought to identify endogenous lipid molecules that act as signaling mediators of autophagy in differentiated SH-SY5Y cells, a commonly used dopaminergic neuron-like cell model. In order to accomplish this goal, we assessed the role of a fatty acid-binding protein (FABP) family member on autophagy due to its function as an intracellular lipid chaperone. We focused specifically upon FABP5 due to its heightened expression in dopaminergic neurons within the substantia nigra and SH-SY5Y cells. Here, we report that knockdown of FABP5 resulted in suppression of autophagy in differentiated SH-SY5Y cells suggesting the possibility of an autophagic role for an interacting lipid. A lipidomic screen of FABP5-interacting lipids uncovered hits that include 5-oxo-eicosatetraenoic acid (5OE) and its precursor metabolite, arachidonic acid (AA). Additionally, other long-chain fatty acids were found to bind FABP5, such as stearic acid (SA), hydroxystearic acid (HSA), and palmitic acid (PA). The addition of 5OE, SA, and HSA but not AA or PA, led to potent inhibition of autophagy in SH-SY5Y cells. To identify potential molecular mechanisms for autophagy inhibition by these lipids, RNA-Seq was performed which revealed both shared and divergent signaling pathways between the lipid-treated groups. These findings suggest a role for these lipids in modulating autophagy through diverse signaling pathways and could represent novel therapeutic targets for Parkinson's disease.

Protocol to assess receptor-ligand binding in C. elegans using adapted thermal shift assays

The Caenorhabditis elegans genome encodes a greatly expanded number of nuclear hormone receptors, many of which remain orphaned. Here, we present a protocol to assess ligand-receptor binding in C. elegans using an adapted cellular thermal shift assay and isothermal dose response. We describe steps for growing C. elegans and preparing lysates and compounds. We also detail how to perform and quantify these assays. This protocol can be used to study any soluble receptor. For complete details on the use and execution of this protocol, please refer to Peterson et al. (2023).1.

Targeting the lysosome: Mechanisms and treatments for nonalcoholic fatty liver disease

The multiple functions of the lysosome, including degradation, nutrient sensing, signaling, and gene regulation, enable the lysosome to regulate lipid metabolism at different levels. In this review, I summarize the recent studies on lysosomal regulation of lipid metabolism and the alterations of the lysosome functions in the livers affected by nonalcoholic fatty liver disease (NAFLD). NAFLD is a highly prevalent lipid metabolic disorder. The progression of NAFLD leads to nonalcoholic steatohepatitis (NASH) and other severe liver diseases, and thus the prevention and treatments of NAFLD progression are critically needed. Targeting the lysosome is a promising strategy. I also discuss the current manipulations of the lysosome functions in the preclinical studies of NAFLD and propose my perspectives on potential future directions.

Flavonol glycoside complanatoside A requires FOXO/DAF-16, NRF2/SKN-1, and HSF-1 to improve stress resistances and extend the life span of Caenorhabditis elegans

Aging is associated with the increased risk of most age-related diseases in humans. Complanatoside A (CA) is a flavonoid compound isolated from the herbal medicine Semen Astragali Complanati. CA was reported to have potential anti-inflammatory and anti-oxidative activities. In this study, we investigated whether CA could increase the stress resistance capability and life span of Caenorhabditis elegans. Our results showed that CA could extend the longevity of C. elegans in a dosage-dependent manner, while 50 μM of CA has the best effect and increased the life span of C. elegans by about 16.87%. CA also improved the physiological functions in aging worms, such as enhanced locomotor capacity, and reduced the accumulation of the aging pigment. CA could also reduce the accumulation of toxic proteins (α-synuclein and β-amyloid) and delay the onset of neurodegenerative disorders, such as Alzheimer’s disease and Parkinson’s disease, in models of C. elegans. Further investigation has revealed that CA requires DAF-16/FOXO, SKN-1, and HSF-1 to extend the life span of C. elegans. CA could increase the antioxidation and detoxification activities regulated by transcription factor SKN-1 and the heat resistance by activating HSF-1 that mediated the expression of the chaperone heat shock proteins. Our results suggest that CA is a potential antiaging agent worth further research for its pharmacological mechanism and development for pharmaceutical applications.

Integrating transcriptomics and behavior tests reveals how the C. elegans responds to copper induced aging

Copper (Cu) pollution in water and agricultural soil has always been a worldwide concern. This research aims to investigate the health effects of copper exposure on Caenorhabditis elegans (C. elegans) under the existing environmental quality standards (1 mg/L and 2 mg/L) via lifespan, reproduction, biological markers and transcriptome analysis. The results showed that copper of these two environmental standards shorten the lifespan of nematodes, reduced the brood size, reduced the frequency of pharyngeal pumps and prolonged defecation time as aging-related behaviors, and increased the levels of aging-related markers ROS, MDA and H₂O₂. There was a certain effect trend for the two exposure concentrations. Further, the possible molecular mechanism of copper-induced aging and reproductive effects on C. elegans was explored. Differential gene expression analysis was performed, and 2332 genes (567 up- and 1765 down-regulated genes) in the 1 mg/L group, 2449 DEGs (724 up- and 1725 down-regulated genes) in the 2 mg/L group in response to copper treatment. The top 20 regulated genes were vit (vit-1, vit-3, vit-4) genes, col genes (col-35, col-72, col-114, col-123, col-164, col-183, col-185), eea-1, him-18 and grl-20, which suggested that cuticle collagen synthesis and yolk expression were disrupted by copper. Analysis of KEGG pathway showed copper exposure widely affects longevity regulation pathways, thereby promoting aging. In summary, the sequencing results extensively and deeply reveal the health hazards of environmentally relevant doses of copper exposure to C. elegans, and behavioral testing verified that copper promoted aging of C. elegans.

Lipid metabolism and lipid signals in aging and longevity

Lipids play crucial roles in regulating aging and longevity. In the past few decades, a series of genetic pathways have been discovered to regulate lifespan in model organisms. Interestingly, many of these regulatory pathways are linked to lipid metabolism and lipid signaling. Lipid metabolic enzymes undergo significant changes during aging and are regulated by different longevity pathways. Lipids also actively modulate lifespan and health span as signaling molecules. In this review, we summarize recent insights into the roles of lipid metabolism and lipid signaling in aging and discuss lipid-related interventions in promoting longevity.

Molecular Mechanisms of Lysosome and Nucleus Communication

Lysosomes transcend the role of degradation stations, acting as key nodes for interorganelle crosstalk and signal transduction. Lysosomes communicate with the nucleus through physical proximity and functional interaction. In response to external and internal stimuli, lysosomes actively adjust their distribution between peripheral and perinuclear regions and modulate lysosome-nucleus signaling pathways; in turn, the nucleus fine-tunes lysosomal biogenesis and functions through transcriptional controls. Changes in coordination between these two essential organelles are associated with metabolic disorders, neurodegenerative diseases, and aging. In this review, we address recent advances in lysosome-nucleus communication by multi-tiered regulatory mechanisms and discuss how these regulations couple metabolic inputs with organellar motility, cellular signaling, and transcriptional network.

Lysosomes: Signaling Hubs for Metabolic Sensing and Longevity

Lysosomes are sites of active metabolism in a cell. They contain various hydrolases that degrade extracellular and intracellular materials during endocytosis and autophagy, respectively. In addition to their long-recognized roles in degradation and recycling, emerging studies have revealed that lysosomes are organizing centers for signal transduction. Lysosome-derived signaling plays crucial roles in regulating nutrient sensing, metabolic adaptation, organelle crosstalk, and aging. In particular, how the degradative role of the lysosome cooperates with its signaling functions to actively modulate lifespan is beginning to be unraveled. This review describes recent advances in the role of the lysosome as a 'signaling hub' that uses three different lysosome-derived signaling pathways to integrate metabolic inputs, organelle interactions, and the control of longevity.