The Scap-SREBP1-S1P/S2P lipogenesis signal orchestrates the homeostasis and spatiotemporal activation of NF-κB

Deciphering the interaction between the expression of LRP2 served as a mitochondrial metabolism-related gene and prognosis in colon cancer integrating multi-omics analysis

BACKGROUND

Colon adenocarcinoma (COAD) is increasingly prevalent among patients under 50 years old, and the 5-year survival rate for patients with metastasis is less than 20%. Identifying significant biomarkers and therapeutic targets is crucial. We investigated the expression of LRP2 in COAD and its prognostic value utilizing single-cell sequencing and transcriptomics datasets, which was conducted preliminary validation at the patient samples and cellular levels as well.

METHODS

Based on differential gene expression of tumor samples and normal tissues in The Cancer Genome Atlas (TCGA), we performed consensus clustering, univariate and multivariate Cox regression analysis applying 1,234 mitochondrial metabolism-related genes (MMRGs) to identify some essential genes associated with poor prognosis in COAD patients. We validated survival outcome and biological function of the target gene leveraging single-cell sequencing and transcriptomics datasets from Gene Expression Omnibus (GEO), and evaluated the value of the target gene in the clinical pathology stage of COAD patients. Simultaneously, the expression levels of critical gene were detected in the diverse tissues of COAD by immunohistochemistry (IHC) staining. Transcriptomics data was continuously implemented to compare the discrepancy between the expression levels of the target gene and somatic mutation burden, inspecting the key pathways of the target gene by gene set enrichment analysis (GSEA) and examining its drug sensitivity synthetically in the CellMiner databases. The proliferative capacity augmented in LRP2-overexpressed colon cancer cells was determined employing cell counting kit-8 (CCK-8) and flow cytometry assays.

RESULTS

LRP2 served as a key mitochondrial metabolism-related gene was assessed clinical prognosis in COAD patients according to the TCGA database. High expression of LRP2 was prominently associated with poor prognosis in COAD patients (P < 0.05), which was validated by GEO databases, and the expression levels of LRP2 were positively related to clinical pathological stage simultaneously (P < 0.05). Some specific cell types were clustered and proliferation pathways were immensely enriched, which were correlated with LRP2 in two single-cell sequencing datasets. The mutation profiles displayed remarkable differences in two levels of LRP2, we also observed high expressions of LRP2 were immensely correlated with high tumor mutation burden (TMB) and unfavorable prognosis in these patients (P < 0.05). LRP2 was significantly enriched in multiple cancer proliferation-related pathways, and the noteworthy correlation between LRP2 and the sensitivity to various drugs was identified (P < 0.05). The expression levels of LRP2 were multifarious in different COAD patients based on IHC staining. LRP2-overpression could stimulate the proliferation capability of HCT116 and SW480 cell lines markedly (P < 0.05).

CONCLUSION

The expression levels of LRP2 were intimately correlated with gene mutations, prognosis, pathological stage and the sensitivity to anticancer drugs in COAD. Augmented levels of LRP2 would manifest poor prognosis, which furnished novel insights for clinical diagnosis and treatment in COAD. LRP2 could extensively facilitate the proliferation ability of colon cell lines.

Bicuculline ameliorates metabolic dysfunction-associated steatotic liver disease by inhibiting the nuclear factor-kappa B pathway and reducing lipid accumulation

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) has emerged as a prominent and pervasive global health challenge. Bicuculline (BIC), which is a key active component of the anti-MASLD prescription "Eight Zhes Decoction", has been preliminarily shown by our research team to have significant potential in treating MASLD.

AIM

To determine BIC's efficacy in treating MASLD by regulating lipid metabolism and suppressing hepatic inflammation via nuclear factor-kappa B (NF-κB) pathway, identifying it as a therapeutic candidate.

METHODS

This study explored the potential of BIC in preventing and treating MASLD using zebrafish, cellular (HepG2 and AML12), and mouse models.

RESULTS

Our results indicate that BIC significantly reduces lipid accumulation and inflammation both in vivo and in vitro. Transcriptomic analysis suggested that the anti-MASLD effects of BIC are linked to the inhibition of the NF-κB pathway, which plays a critical role in mitigating inflammation and lipid deposition.

CONCLUSION

This study is the first to demonstrate that BIC specifically alleviates lipid accumulation and hepatic steatosis in MASLD models via the NF-κB signaling pathway. Overall, BIC has emerged as a promising candidate for treating MASLD.

Insulin-induced gene 2 alleviates ischemia-reperfusion injury in steatotic liver by inhibiting GPX4-dependent ferroptosis

Hepatic steatosis significantly elevates the vulnerability of the graft to ischemia-reperfusion (I/R) injury during liver transplantation (LT). We investigated the protective role of insulin-induced gene 2 (Insig2) in steatotic liver's I/R injury and underlying mechanisms. Employing mouse model with Insig2 knock-out or hepatocyte-specific overexpression and high-fat diets to induce steatosis, we subjected these mice to hepatic I/R injury. The primary hepatocytes isolated from steatotic liver were used in in vitro hypoxia/reoxygenation (H/R) experiment. Our integrated in vivo and in vitro approach uncovered that Insig2 deficiency exacerbated steatotic liver's damage following hepatic I/R injury, whereas its overexpression offers protection. Mechanically, integrative analysis of transcriptome, proteome, and metabolome found that Insig2 deficiency disturbed lipid metabolism and oxidative stress homeostasis, particularly inhibiting GPX4 expression to induce ferroptosis. Furthermore, chemical inhibition of ferroptosis reversed the deleterious effect of Insig2 deficiency; whereas the protective influence of Insig2 overexpression was negated by the target inhibition of GPX4, leading to an exacerbation of hepatic I/R damage. These insights underscored the potential of the Insig2-GPX4 axis as a therapeutic target, presenting a novel avenue for enhancing the resilience of steatotic liver grafts against I/R injury.

Characterization of subcutaneous and visceral de-differentiated fat cells

OBJECTIVE

The capacity of mature adipocytes to de-differentiate into fibroblast-like cells has been demonstrated in vitro and a few, rather specific in vivo conditions. A detailed comparison between de-differentiated fat (DFAT) cells and adipose stem and progenitor cells (ASPCs) from different adipose depots is yet to be conducted. Moreover, whether de-differentiation of mature adipocytes from classical subcutaneous and visceral depots occurs under physiological conditions remains unknown.

METHODS

Here, we used in vitro "ceiling culture", single cell/nucleus RNA sequencing, epigenetic anaysis and genetic lineage tracing to address these unknowns.

RESULTS

We show that in vitro-derived DFAT cells have lower adipogenic potential and distinct cellular composition compared to ASPCs. In addition, DFAT cells derived from adipocytes of inguinal origin have dramatically higher adipogenic potential than DFAT cells of the epididymal origin, due in part to enhanced NF-KB signaling in the former. We also show that high-fat diet (HFD) feeding enhances DFAT cell colony formation and re-differentiation into adipocytes, while switching from HFD to chow diet (CD) only reverses their re-differentiation. Moreover, HFD deposits epigenetic changes in DFAT cells and ASPCs that are not reversed after returning to CD. Finally, combining genetic lineage tracing and single cell/nucleus RNA sequencing, we demonstrate the existence of DFAT cells in inguinal and epididymal adipose depots in vivo, with transcriptomes resembling late-stage ASPCs.

CONCLUSIONS

These data uncover the cell type- and depot-specific properties of DFAT cells, as well as their plasticity in response to dietary intervention. This knowledge may shed light on their role in life style change-induced weight loss and regain.

Classification and functional characterization of regulators of intracellular STING trafficking identified by genome-wide optical pooled screening

Stimulator of interferon genes (STING) traffics across intracellular compartments to trigger innate responses. Mutations in factors regulating this process lead to inflammatory disorders. To systematically identify factors involved in STING trafficking, we performed a genome-wide optical pooled screen (OPS). Based on the subcellular localization of STING in 45 million cells, we defined 464 clusters of gene perturbations based on their cellular phenotypes. A secondary, higher-dimensional OPS identified 73 finer clusters. We show that the loss of the gene of unknown function C19orf25, which clustered with USE1, a protein involved in Golgi-to-endoplasmic reticulum (ER) transport, enhances STING signaling. Additionally, HOPS deficiency delayed STING degradation and consequently increased signaling. Similarly, GARP/RIC1-RGP1 loss increased STING signaling by delaying STING Golgi exit. Our findings demonstrate that genome-wide genotype-phenotype maps based on high-content cell imaging outperform other screening approaches and provide a community resource for mining factors that impact STING trafficking and other cellular processes.

Reprogramming SREBP1-dependent lipogenesis and inflammation in high-risk breast with licochalcone A: a novel path to cancer prevention

Background

Anti-estrogens have had limited impact on breast cancer (BC) prevention. Novel agents with better tolerability, and efficacy beyond estrogen receptor (ER) positive BC are needed. We studied licochalcone A (LicA) for ER-agnostic BC prevention.

Methods

We evaluated antiproliferative effects of LicA in seven breast cell lines and its suppression of ER+ and ER- xenograft tumors in mice. High-risk human breast tissue was treated with LicA ex vivo , followed by RNA sequencing and metabolism flux modeling. Confirmatory testing was performed in an independent specimen set and ER+/- BC cell lines using NanoString metabolic panel, proteomics, western blots, and spatiotemporally resolved cholesterol quantification in single cells.

Results

LicA suppressed proliferation in vitro and xenograft tumor growth in vivo . It downregulated pivotal steps in PI3K-AKT-SREBP1-dependent lipogenesis, suppressed PI3K and AKT phosphorylation, SREBP1 protein expression, and cholesterol levels in the plasma membrane inner leaflet, to the levels in normal breast cells. LicA also suppressed prostaglandin E2 synthesis and PRPS1-catalyzed de novo nucleotide biosynthesis, stalling proliferation; further evident by reduced MKI67 and BCL2 proteins.

Conclusions

LicA targets SREBP1, a central regulator of lipogenesis and immune response, reducing pro-tumorigenic aberrations in lipid homeostasis and inflammation. It is a promising non-endocrine candidate for BC prevention.

Adipocyte microRNA-802 promotes adipose tissue inflammation and insulin resistance by modulating macrophages in obesity

Adipose tissue inflammation is now considered to be a key process underlying metabolic diseases in obese individuals. However, it remains unclear how adipose inflammation is initiated and maintained or the mechanism by which inflammation develops. We found that microRNA-802 (Mir802) expression in adipose tissue is progressively increased with the development of dietary obesity in obese mice and humans. The increasing trend of Mir802 preceded the accumulation of macrophages. Adipose tissue-specific knockout of Mir802 lowered macrophage infiltration and ameliorated systemic insulin resistance. Conversely, the specific overexpression of Mir802 in adipose tissue aggravated adipose inflammation in mice fed a high-fat diet. Mechanistically, Mir802 activates noncanonical and canonical NF-κB pathways by targeting its negative regulator, TRAF3. Next, NF-κB orchestrated the expression of chemokines and SREBP1, leading to strong recruitment and M1-like polarization of macrophages. Our findings indicate that Mir802 endows adipose tissue with the ability to recruit and polarize macrophages, which underscores Mir802 as an innovative and attractive candidate for miRNA-based immune therapy for adipose inflammation.

Protective Role of Sphingosine-1-Phosphate During Radiation-Induced Testicular Injury

The impact of ionizing radiation on the male reproductive system is gaining increasing attention, particularly when it comes to testicular damage, which may result in decreased sperm quality and hormonal imbalances. Finding effective protective measures to mitigate testicular damage caused by radiation has become a focal point in the biomedical field. S1P, an essential biological signaling molecule, has garnered significant interest due to its multiple roles in regulating cellular functions and its protective effects against radiation-induced testicular injury. S1P not only effectively reduces the generation of ROS induced by radiation but also alleviates oxidative stress by enhancing the activity of antioxidant enzymes. Furthermore, S1P inhibits radiation-induced cell apoptosis by regulating the expression of anti-apoptotic and pro-apoptotic proteins. Additionally, S1P alleviates radiation-induced inflammation by inhibiting the production of inflammatory factors, thereby further protecting testicular tissue. In summary, S1P effectively reduces radiation-induced testicular damage through multiple mechanisms, offering a promising therapeutic approach to safeguard male reproductive health. Future research should explore the specific mechanisms of action and clinical application potential of S1P, aiming to contribute significantly to the prevention and treatment of radiation damage.

Multi-omics analyses were combined to construct ubiquitination-related features in colon adenocarcinoma and identify ASNS as a novel biomarker

Background

As one of the malignant tumors with the highest incidence and fatality in the world, colon adenocarcinoma (COAD) has a very complex pathogenic mechanism, which has not yet been fully elucidated. Ubiquitin can regulate cell proliferation, cell cycle, apoptosis, DNA damage repair, and other processes by changing the activity of substrate proteins or causing ubiquitin-proteasome degradation. These are the key links in the pathogenesis of COAD, and ubiquitin plays an important role in the occurrence and development of COAD.

Methods

We integrated transcriptomics, single-cell and clinical omics, and TCGA and GEO databases of COAD patient data. Cox and Lasso regression was employed to assess ubiquitination genes in COAD for generating ubiquitination-related features. The aim was to evaluate the prognostic value of these features for tumors and their impact on the immune microenvironment. At the same time, the expression level of model genes was further analyzed using single-cell data. Finally, the expression and function of ASNS, a key gene for this trait, were detected in vitro.

Results

In our study, based on identifiable changes in the expression of marker genes, this feature can be used to classify patients with COAD. Kaplan-Meier survival analysis indicated that those with elevated risk scores in each cohort experienced inferior outcomes. There is good validation in both the training queue and the validation queue. The results of the immune infiltration analysis showed that the immune infiltration rate was significantly increased in the high-risk group. After the knockdown of ASNS, an important gene in the signature, the activity and migration capacity of SW620 and RKO cell lines and colony formation capacity were dramatically reduced in cell tests.

Conclusion

We screened ubiquitination-related genes and constructed ubiquitination-related features, which can be used as reliable prognostic indicators of COAD. ASNS was identified as a possible biomarker for COAD.

Rhodium nanozyme mitigates RPE degeneration and preserves vision in age-related macular degeneration via antioxidant and anti-inflammatory mechanisms

Age-related macular degeneration (AMD) is the leading cause of blindness among elderly people worldwide. However, there are currently no effective treatments for AMD. Oxidative stress-induced retinal pigment epithelium (RPE) degeneration and the inflammatory response are the main causes of AMD. In this study, a polyethylene glycol (PEG)-coated rhodium nanozyme (PEG-RhZ) with excellent reactive oxygen species (ROS) and reactive nitrogen species (RNS) elimination capability was synthesized for the treatment of AMD. PEG-RhZs protected RPE cell viability and barrier function upon exposure to oxidative stress stimuli. Additionally, microglial migration and iNOS, IL-1β and TNF-α expression were inhibited by PEG-RhZs. In the acute phase of the AMD model, PEG-RhZs significantly alleviated RPE oxidative damage and inhibited microglial activation. In the late stage of the AMD model, PEG-RhZs reduced photoreceptor loss and improved vision impairment. Furthermore, PEG-RhZs showed good biocompatibility and stability both in vitro and in vivo. Collectively, our findings suggest the therapeutic potential of PEG-RhZs for AMD treatment. STATEMENT OF SIGNIFICANCE: AMD is a kind of retinal degenerative disease that poses heavy health burden globally. PEG-RhZs exhibiting robust ROS and RNS scavenging capabilities have shown promise in safeguarding retinal pigment epithelium (RPE) from oxidative stress, suppressing microglia activation and the secretion of pro-inflammatory molecules, mitigating loss of retinal photoreceptor cells, and ameliorating visual impairment. The commendable antioxidant properties, biological safety, and biostability of PEG-RhZs offer valuable insights for the clinical management of AMD.

Inflammasome activity regulation by PUFA metabolites

Oxidative stress and the accompanying chronic inflammation constitute an important metabolic problem that may lead to pathology, especially when the body is exposed to physicochemical and biological factors, including UV radiation, pathogens, drugs, as well as endogenous metabolic disorders. The cellular response is associated, among others, with changes in lipid metabolism, mainly due to the oxidation and the action of lipolytic enzymes. Products of oxidative fragmentation/cyclization of polyunsaturated fatty acids (PUFAs) [4-HNE, MDA, 8-isoprostanes, neuroprostanes] and eicosanoids generated as a result of the enzymatic metabolism of PUFAs significantly modify cellular metabolism, including inflammation and the functioning of the immune system by interfering with intracellular molecular signaling. The key regulators of inflammation, the effectiveness of which can be regulated by interacting with the products of lipid metabolism under oxidative stress, are inflammasome complexes. An example is both negative or positive regulation of NLRP3 inflammasome activity by 4-HNE depending on the severity of oxidative stress. 4-HNE modifies NLRP3 activity by both direct interaction with NLRP3 and alteration of NF-κB signaling. Furthermore, prostaglandin E2 is known to be positively correlated with both NLRP3 and NLRC4 activity, while its potential interference with AIM2 or NLRP1 activity is unproven. Therefore, the influence of PUFA metabolites on the activity of well-characterized inflammasome complexes is reviewed.

Research progress of SREBP and its role in the pathogenesis of autoimmune rheumatic diseases

Autoimmune rheumatic diseases comprise a group of immune-related disorders characterized by non-organ-specific inflammation. These diseases include systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), ankylosing spondylitis (AS), gout, among others. Typically involving the hematologic system, these diseases may also affect multiple organs and systems. The pathogenesis of autoimmune rheumatic immune diseases is complex, with diverse etiologies, all associated with immune dysfunction. The current treatment options for this type of disease are relatively limited and come with certain side effects. Therefore, the urgent challenge remains to identify novel therapeutic targets for these diseases. Sterol regulatory element-binding proteins (SREBPs) are basic helix-loop-helix-leucine zipper transcription factors that regulate the expression of genes involved in lipid and cholesterol biosynthesis. The expression and transcriptional activity of SREBPs can be modulated by extracellular stimuli such as polyunsaturated fatty acids, amino acids, glucose, and energy pathways including AKT-mTORC and AMP-activated protein kinase (AMPK). Studies have shown that SREBPs play roles in regulating lipid metabolism, cytokine production, inflammation, and the proliferation of germinal center B (GCB) cells. These functions are significant in the pathogenesis of rheumatic and immune diseases (Graphical abstract). Therefore, this paper reviews the potential mechanisms of SREBPs in the development of SLE, RA, and gout, based on an exploration of their functions.

Classification and functional characterization of regulators of intracellular STING trafficking identified by genome-wide optical pooled screening

STING is an innate immune sensor that traffics across many cellular compartments to carry out its function of detecting cyclic di-nucleotides and triggering defense processes. Mutations in factors that regulate this process are often linked to STING-dependent human inflammatory disorders. To systematically identify factors involved in STING trafficking, we performed a genome-wide optical pooled screen and examined the impact of genetic perturbations on intracellular STING localization. Based on subcellular imaging of STING protein and trafficking markers in 45 million cells perturbed with sgRNAs, we defined 464 clusters of gene perturbations with similar cellular phenotypes. A higher-dimensional focused optical pooled screen on 262 perturbed genes which assayed 11 imaging channels identified 73 finer phenotypic clusters. In a cluster containing USE1, a protein that mediates Golgi to ER transport, we found a gene of unknown function, C19orf25. Consistent with the known role of USE1, loss of C19orf25 enhanced STING signaling. Other clusters contained subunits of the HOPS, GARP and RIC1-RGP1 complexes. We show that HOPS deficiency delayed STING degradation and consequently increased signaling. Similarly, GARP/RIC1-RGP1 loss increased STING signaling by delaying STING exit from the Golgi. Our findings demonstrate that genome-wide genotype-phenotype maps based on high-content cell imaging outperform other screening approaches, and provide a community resource for mining for factors that impact STING trafficking as well as other cellular processes observable in our dataset.