Perilipin-2 limits remyelination by preventing lipid droplet degradation

Proteome characterization of liver-kidney comorbidity after microbial sepsis

Sepsis is a life-threatening condition that occurs when the body responds to an infection but subsequently triggers widespread inflammation and impaired blood flow. These pathologic responses can rapidly cause multiple organ dysfunction or failure either one by one or simultaneously. The fundamental common mechanisms involved in sepsis-induced multiple organ dysfunction remain unclear. Here, employing quantitative global and phosphoproteomics, we examine the liver's temporal proteome and phosphoproteome changes after moderate sepsis induced by cecum ligation and puncture. In total, 4593 global proteins and 1186 phosphoproteins according to 3275 phosphosites were identified. To characterize the liver-kidney comorbidity after sepsis, we developed a mathematical model and performed cross-analyses of liver and kidney proteome data obtained from the same set of mice. Beyond immune response, we showed the commonly disturbed pathways and key regulators of the liver-kidney comorbidity are linked to energy metabolism and consumption. Our data provide open resources to understand the communication between the liver and kidney as they work to fight infection and maintain homeostasis.

Scutellarin inhibits oleic acid induced vascular smooth muscle foam cell formation via activating autophagy and inhibiting NLRP3 inflammasome activation

Abnormalities in vascular smooth muscle cells (VSMCs) are pivotal in the pathogenesis of cardiovascular pathologies such as atherosclerosis and hypertension. Scutellarin (Scu), a flavonoid derived from marigold flowers, exhibits a spectrum of biological activities including anti-inflammatory, antioxidant, antitumor, immunomodulatory and antimicrobial effects. Notably, Scu has demonstrated the capacity to mitigate vascular endothelial damage and prevent atherosclerosis via its antioxidative properties. Nevertheless, the influence of Scu on the formation of VSMC-derived foam cells remains underexplored. In this study, Scu was evidenced to efficaciously attenuate oleic acid (OA)-induced lipid accumulation and the upregulation of adipose differentiation-associated protein Plin2 in a dose- and time-responsive manner. We elucidated that Scu effectively diminishes OA-provoked VSMC foam cell formation. Further, it was established that Scu pretreatment augments the protein expression of LC3B-II and the mRNA levels of Map1lc3b and Becn1, concurrently diminishing the protein levels of the NLRP3 inflammasome compared to the OA group. Activation of autophagy through rapamycin attenuated NLRP3 inflammasome protein expression, intracellular lipid droplet content and Plin2 mRNA levels. Scu also counteracted the OA-induced decrement of LC3B-II levels in the presence of bafilomycin-a1, facilitating the genesis of autophagosomes and autolysosomes. Complementarily, in vivo experiments revealed that Scu administration substantially reduced arterial wall thickness, vessel wall cross-sectional area, wall-to-lumen ratio and serum total cholesterol levels in comparison to the high-fat diet model group. Collectively, our findings suggest that Scu attenuates OA-induced VSMC foam cell formation through the induction of autophagy and the suppression of NLRP3 inflammasome activation.

Boosting Microglial Lipid Metabolism via TREM2 Signaling by Biomimetic Nanoparticles to Attenuate the Sevoflurane-Induced Developmental Neurotoxicity

Lipid metabolism has been considered as a potential therapeutic target in sevoflurane-induced neurotoxicity that can potentially affect the learning and memory function in the developmental brain. Recently, triggering receptor expressed on myeloid cells 2 (TREM2) is identified as a crucial step in regulating lipid metabolism and associated with the pathogenesis of neurodegenerative diseases. Herein, it is reported that quercetin modified Cu2- x Se (abbreviated as CSPQ) nanoparticles can ameliorate sevoflurane-induced neurotoxicity by tuning the microglial lipid metabolism and promoting microglial M2-like polarization via TREM2 signaling pathway, in which the apolipoprotein E (ApoE), and adenosine triphosphate-binding cassette transporters (ABCA1 and ABCG1) levels are upregulated. Furthermore, the protective effects of CSPQ nanoparticles against sevoflurane-induced neurotoxicity via TREM2 are further demonstrated by the small interfering RNA (siRNA)-TREM2 transfected BV2 cells, which are obviously not influenced by CSPQ nanoparticles. The cell membrane coated CSPQ (referred as CSPQ@CM) nanoparticles can significantly reduce sevoflurane-induced learning and memory deficits, improve lipid metabolism dysfunction, and promote the remyelination in the hippocampus of mice. The study shows great potential of targeting microglial lipid metabolism in promoting remyelination of neurons for treatment of neurotoxicity and neurodegenerative diseases.

Nanointegrative In Situ Reprogramming of Tumor-Intrinsic Lipid Droplet Biogenesis for Low-Dose Radiation-Activated Ferroptosis Immunotherapy

Low-dose radiotherapy (LDR) has shown significant implications for inflaming the immunosuppressive tumor microenvironment (TME). Surprisingly, we identify that FABP-dependent lipid droplet biogenesis in tumor cells is a key determinant of LDR-evoked cytotoxic and immunostimulatory effects and developed a nanointegrated strategy to promote the antitumor efficacy of LDR through cooperative ferroptosis immunotherapy. Specifically, TCPP-TK-PEG-PAMAM-FA, a nanoscale multicomponent functional polymer with self-assembly capability, was synthesized for cooperatively entrapping hafnium ions (Hf4+) and HIF-1α-inhibiting siRNAs (siHIF-1α). The TCPP@Hf-TK-PEG-PAMAM-FA@siHIF-1α nanoassemblies are specifically taken in by folate receptor-overexpressing tumor cells and activated by the elevated cellular ROS stress. siHIF-1α could readily inhibit the FABP3/7 expression in tumor cells via HIF-1α-FABP3/7 signaling and abolish lipid droplet biogenesis for enhancing the peroxidation susceptibility of membrane lipids, which synergizes with the elevated ROS stress in the context of Hf4+-enhanced radiation exposure and evokes pronounced ferroptotic damage in vital membrane structures. Interestingly, TCPP@Hf-TK-PEG-PAMAM-FA@siHIF-1α-enhanced ferroptotic biomembrane damage also facilitates the exposure of tumor-associated antigens (TAAs) to promote post-LDR immunotherapeutic effects, leading to robust tumor regression in vivo. This study offers a nanointegrative approach to boost the antitumor effects of LDR through the utilization of tumor-intrinsic lipid metabolism.

RIT1 regulation of CNS lipids RIT1 deficiency Alters cerebral lipid metabolism and reduces white matter tract oligodendrocytes and conduction velocities

Oligodendrocytes (OLs) generate lipid-rich myelin membranes that wrap axons to enable efficient transmission of electrical impulses. Using a RIT1 knockout mouse model and in situ high-resolution matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) coupled with MS-based lipidomic analysis to determine the contribution of RIT1 to lipid homeostasis. Here, we report that RIT1 loss is associated with altered lipid levels in the central nervous system (CNS), including myelin-associated lipids within the corpus callosum (CC). Perturbed lipid metabolism was correlated with reduced numbers of OLs, but increased numbers of GFAP+ glia, in the CC, but not in grey matter. This was accompanied by reduced myelin protein expression and axonal conduction deficits. Behavioral analyses revealed significant changes in voluntary locomotor activity and anxiety-like behavior in RIT1KO mice. Together, these data reveal an unexpected role for RIT1 in the regulation of cerebral lipid metabolism, which coincide with altered white matter tract oligodendrocyte levels, reduced axonal conduction velocity, and behavioral abnormalities in the CNS.

Challenges in Pharmacological Intervention in Perilipins (PLINs) to Modulate Lipid Droplet Dynamics in Obesity and Cancer

Perilipins (PLINs) are the most abundant proteins in lipid droplets (LD). These LD-associated proteins are responsible for upgrading LD from inert lipid storage structures to fully functional organelles, fundamentally integrated in the lipid metabolism. There are five distinct perilipins (PLIN1-5), each with specific expression patterns and metabolic activation, but all capable of regulating the activity of lipases on LD. This plurality creates a complex orchestrated mechanism that is directly related to the healthy balance between lipogenesis and lipolysis. Given the essential role of PLINs in the modulation of the lipid metabolism, these proteins can become interesting targets for the treatment of lipid-associated diseases. Since reprogrammed lipid metabolism is a recognized cancer hallmark, and obesity is a known risk factor for cancer and other comorbidities, the modulation of PLINs could either improve existing treatments or create new opportunities for the treatment of these diseases. Even though PLINs have not been, so far, directly considered for pharmacological interventions, there are many established drugs that can modulate PLINs activity. Therefore, the aim of this study is to assess the involvement of PLINs in diseases related to lipid metabolism dysregulation and whether PLINs can be viewed as potential therapeutic targets for cancer and obesity.

Remyelination in Multiple Sclerosis: Findings in the Cuprizone Model

Remyelination therapies, which are currently under development, have a great potential to delay, prevent or even reverse disability in multiple sclerosis patients. Several models are available to study the effectiveness of novel compounds in vivo, among which is the cuprizone model. This model is characterized by toxin-induced demyelination, followed by endogenous remyelination after cessation of the intoxication. Due to its high reproducibility and ease of use, this model enjoys high popularity among various research and industrial groups. In this review article, we will summarize recent findings using this model and discuss the potential of some of the identified compounds to promote remyelination in multiple sclerosis patients.