Plasma lipids signify the progression of precancerous gastric lesions to gastric cancer: a prospective targeted lipidomics study.

Rationale: Gastric cancer (GC) is preceded by a stepwise progression of precancerous gastric lesions. Distinguishing individuals with precancerous gastric lesions that have progression potential to GC is an important need. Perturbated lipid metabolism, particularly the dysregulation of de novo lipogenesis, is involved in gastric carcinogenesis. We conducted the first prospective lipidomics study exploring lipidomic signatures for the risk of gastric lesion progression and early GC. Methods: Our two-stage study of targeted lipidomics enrolled 400 subjects from the National Upper Gastrointestinal Cancer Early Detection Program in China, including 200 subjects of GC and different gastric lesions in the discovery and validation stages. Of validation stage, 152 cases with gastric lesions were prospectively followed for the progression of gastric lesions for a median follow-up of 580 days (interquartile range 390-806 days). We examined the lipidomic signatures associated with the risk of advanced gastric lesions and their progression to GC. Our published tissue proteomic data were referred to further investigate highlighted lipids with their biologically related protein expression in gastric mucosa. Results: We identified 11 plasma lipids significantly inversely associated with the risk of gastric lesion progression and GC occurrence. These lipids were integrated as latent profiles to identify 5 clusters of lipid expression that had distinct risk of gastric lesion progression. The latent profiles significantly improved the ability to predict the progression potential of gastric lesions (AUC: 0.82 vs 0.68, Delong's P = 4.6×10-4) and risk of early GC (AUC: 0.81 vs 0.55, P = 6.3×10-5). Significant associations were found between highlighted lipids, their biologically correlated proteins and the risk of GC, supporting the role of the pathways involving monocarboxylic acid metabolism and lipid transport and catabolic process in GC. Conclusions: Our study revealed the lipidomic signatures associated with the risk of gastric lesion progression and GC occurrence, exhibiting translational implications for GC prevention.

The GDSL Lipase MHZ11 Modulates Ethylene Signaling in Rice Roots.

Ethylene plays important roles in plant growth and development, but the regulation of ethylene signaling is largely unclear, especially in crops such as rice (Oryza sativa). Here, by analysis of the ethylene-insensitive mutant mao huzi 11 (mhz11), we identified the GDSL lipase MHZ11, which modulates ethylene signaling in rice roots. MHZ11 localized to the endoplasmic reticulum membrane and has acyl-hydrolyzing activity. This activity affects the homeostasis of sterols in rice roots and is required for root ethylene response. MHZ11 overexpression caused constitutive ethylene response in roots. Genetically, MHZ11 acts with the ethylene receptor ETHYLENE RESPONSE SENSOR2 (OsERS2) upstream of CONSTITUTIVE TRIPLE RESPONSE2 (OsCTR2) and ETHYLENE INSENSITIVE2 (OsEIN2). The mhz11 mutant maintains more OsCTR2 in the phosphorylated form whereas MHZ11 overexpression promotes ethylene-mediated inhibition of OsCTR2 phosphorylation. MHZ11 colocalized with the ethylene receptor OsERS2, and its effect on OsCTR2 phosphorylation requires ethylene perception and initiation of ethylene signaling. The mhz11 mutant overaccumulated sterols and blocking sterol biosynthesis partially rescued the mhz11 ethylene response, likely by reducing receptor-OsCTR2 interaction and OsCTR2 phosphorylation. We propose that MHZ11 reduces sterol levels to impair receptor-OsCTR2 interactions and OsCTR2 phosphorylation for triggering ethylene signaling. Our study reveals a mechanism by which MHZ11 participates in ethylene signaling for regulation of root growth in rice.

Selection for a Zinc-Finger Protein Contributes to Seed Oil Increase during Soybean Domestication.

Seed oil is a momentous agronomical trait of soybean (Glycine max) targeted by domestication in breeding. Although multiple oil-related genes have been uncovered, knowledge of the regulatory mechanism of seed oil biosynthesis is currently limited. We demonstrate that the seed-preferred gene GmZF351, encoding a tandem CCCH zinc finger protein, is selected during domestication. Further analysis shows that GmZF351 facilitates oil accumulation by directly activating WRINKLED1, BIOTIN CARBOXYL CARRIER PROTEIN2, 3-KETOACYL-ACYL CARRIER PROTEIN SYNTHASE III, DIACYLGLYCEROL O-ACYLTRANSFERASE1, and OLEOSIN2 in transgenic Arabidopsis (Arabidopsis thaliana) seeds. Overexpression of GmZF351 in transgenic soybean also activates lipid biosynthesis genes, thereby accelerating seed oil accumulation. The ZF351 haplotype from the cultivated soybean group and the wild soybean (Glycine soja) subgroup III correlates well with high gene expression level, seed oil contents and promoter activity, suggesting that selection of GmZF351 expression leads to increased seed oil content in cultivated soybean. Our study provides novel insights into the regulatory mechanism for seed oil accumulation, and the manipulation of GmZF351 may have great potential in the improvement of oil production in soybean and other related crops.