Hypothalamus transcriptome signatures underlying metabolic malprogramming in offspring mice exposed to a maternal obesogenic environment

Purpose: Identify the potential effector that might responding to the irritated hypothalamic ER stress as early as postnatal resulting from maternal obesity exposure. Methods: Three-week-old male offspring were selected for extracting RNA sample from the three groups (triplicate in sample): LP (Lg42_P1, Lg63_P2, Lg63_P3), HP (Hg43_P1, Hg43_P2, Hg13_P3) and HA (Hg43_A1, Hg43_A2, Hg13_A3). After standard RNA quantification and qualification, library preparation, clustering, sequencing and quality control, reads were mapped to the reference genome, and quantified of gene expression level with FPKM. The data were further processed for differential expression and other functional analysis. Results: We identified 789 differentially expressed genes (DEGs) (DESeq2, pvalue<0.05, |log2FoldChange|>0.0) in the mice from HP compared with those from LP, of which 408 (52%) were upregulated, while 381 (48%) downregulated. Whereas, for those of HA versus HP, 726 DEGs were detected, with 401 (55%) upregulated and 325 (45%) downregulated. There was a total of 158 overlapped DEGs between the two compared groups. In the following Gene Ontology enrichment analysis, we found that the upregulated DEGs in the HP group were significantly enriched in the categories related to molecular chaperon mediated protein processing. While for those downregulated DEGs in HA, similar theme was enriched with most of the genes from family members of the heat shock protein (Hsp), especially Hsp70. We validated the alteration of two members of Hsp70 in the hypothalamus of the weaning offspring given their crucial role in the stress response. Conclusions: Hspa1b might be the potential effector for the irritated early hypothalamic ER stress and the root of unbalanced stress balance in the hypothalamus undergoing feeding-related circuit axon projection in male offspring from obese dams. Animal model building and RNA sample extraction: Five-week-old ICR female mice were given low-fat diet (LFD) or high-fat high-sucrose diet (HFHS) for five weeks before breeding. The dams were keeping with the same diets of the pregestational one during the gestation and lactation. Ten pups per litter were adapted on the day of production. During the postnatal 4 to 16, pups from dams feeding with LFD or HFHS were peripherally injected with PBS (vehicle) or 4-PBA daily. Thus there were offspring from LFD fed dams receiving vehicle (referred to as LP) or from HFHS fed dams receiving vehicle (referred to as HP) or 4-PBA (referred to as HA). At weaning, male offspring were selected for extracting RNA sample from the three groups (triplicate in sample): LP (Lg42_P1, Lg63_P2, Lg63_P3), HP (Hg43_P1, Hg43_P2, Hg13_P3) and HA (Hg43_A1, Hg43_A2, Hg13_A3).