[Statistical analysis of disability-adjusted life years for stomach and colorectal cancers in Changning District of Shanghai].

Objectives: To analyze the status and temporal changes of disability-adjusted life year (DALY) for stomach and colorectal cancers among registered permanent residents in Changning District of Shanghai Municipality, and provide scientific basis for the prevention and treatment of stomach and colorectal cancers in this district. Methods: Using the cancer registration data of stomach and colorectal cancers from 2002 to 2019, we estimated the indices such as the DALYs, the DALY crude rates, the age-standardized DALY rates, etc. Then we used the Joinpoint regression model to calculate the average annual percent change (AAPC) and annual percent change (APC) to explore the temporal variations in different periods. Results: The DALYs of stomach and colorectal cancers in Changning District from 2002 to 2019 were 55 931 person years and 65 252 person years, respectively. The crude rates of DALY were 512.16/105 and 597.51/105, respectively. We observed a higher disease burden in men than in women, and the peak rate of DALY in stomach cancer was in the 75-79 years age group, while in colorectal cancer the rate was in the 85-years-or-older age group. Joinpoint regression analysis showed that from 2002 to 2019, the age-standardized DALY rate of stomach cancer showed a downward trend (AAPC=-3.86%, P＜0.05), while the trend of colorectal cancer was not statistically significant(AAPC=-0.08%, P＞0.05). However, the trends in the age-standardized DALY rates of colorectal cancer were different between males and females, with males showing an upward trend (AAPC=1.24%, P＜0.05) and females showing a downward trend (AAPC=-1.67%, P＜0.05). Conclusions: The DALY of stomach and colorectal cancers in Changning District of Shanghai showed a decreasing trend. Males and the middle-aged and elderly populations are still the key targets for disease prevention and control in this district.

Overexpression of SREBP1 (sterol regulatory element binding protein 1) promotes de novo fatty acid synthesis and triacylglycerol accumulation in goat mammary epithelial cells.

Sterol regulatory element binding protein 1 (SREBP1; gene name SREBF1) is known to be the master regulator of lipid homeostasis in mammals, including milk fat synthesis. The major role of SREBP1 in controlling milk fat synthesis has been demonstrated in bovine mammary epithelial cells. Except for a demonstrated role in controlling the expression of FASN, a regulatory role of SREBP1 on milk fat synthesis is very likely, but has not yet been demonstrated in goat mammary epithelial cells (GMEC). To explore the regulatory function of SREBP1 on de novo fatty acids and triacylglycerol synthesis in GMEC, we overexpressed the mature form of SREBP1 (active NH2-terminal fragment) in GMEC using a recombinant adenovirus vector (Ad-nSREBP1), with Ad-GFP (recombinant adenovirus of green fluorescent protein) as control, and infected the GMEC for 48 h. In infected cells, we assessed the expression of 20 genes related to milk fat synthesis using real time-quantitative PCR, the protein abundance of SREBP1 and FASN by Western blot, the production of triacylglycerol, and the fatty acid profile. Expression of SREBF1 was modest in mammary compared with the other tissues in dairy goats but its expression increased approximately 30-fold from pregnancy to lactation. The overexpression of the mature form of SREBP1 was confirmed by >200-fold higher expression of SREBF1 in Ad-nSREBP1 compared with Ad-GFP. We observed no changes in amount of the precursor form of SREBP1 protein but a >10-fold increase of the mature form of SREBP1 protein with Ad-nSREBP1. Compared with Ad-GFP cells (control), Ad-nSREBP1 cells had a significant increase in expression of genes related to long-chain fatty acid activation (ACSL1), transport (FABP3), desaturation (SCD1), de novo synthesis of fatty acids (ACSS2, ACLY, IDH1, ACACA, FASN, and ELOVL6), and transcriptional factors (NR1H3 and PPARG). We observed a >10-fold increase in expression of INSIG1 but SCAP was downregulated by Ad-nSREBP1. Among genes related to milk fat synthesis and lipid droplet formation, only LPIN1 and DGAT1 were upregulated by Ad-nSREBP1. Compared with the Ad-GFP, the cellular triacylglycerol content was higher and the percentage of C16:0 and C18:1 increased, whereas that of C16:1, C18:0, and C18:2 decreased in Ad-nSREBP1 cells. Overall, the data provide strong support for a central role of SREBP1 in the regulation of milk fat synthesis in goat mammary cells.

Peroxisome proliferator-activated receptor γ1 and γ2 isoforms alter lipogenic gene networks in goat mammary epithelial cells to different extents.

In nonruminants, the alternative splicing of peroxisome proliferator-activated receptor γ (PPARG) generates PPARG1 and PPARG2 isoforms. Although transcriptional control differences between isoforms have been reported in human adipose tissue, their roles in ruminant mammary cells are not well known. To assess which of these isoforms is more closely associated with the regulation of mammary lipogenic pathways, their tissue distribution was analyzed and the expression of key genes regulating lipogenic gene networks was measured after overexpression of the 2 isoforms in goat mammary epithelial cells (GMEC). The expression of PPARG2 was markedly greater in adipose tissue, whereas PPARG1 is the main isoform in goat mammary tissue (ratio of PPARG1:PPARG2 was close to 37:1). As was reported in previous work, PPARG1 upregulated the transcription regulators SREBF1 and PPARG and the lipogenic genes FASN, ACACA, and SCD. Along with a tendency for greater expression of AGPAT6, DGAT1, and PLIN2, these data suggest that PPARG1 is the isoform controlling lipogenesis in mammary cells. Addition of the PPARG ligand rosiglitazone (ROSI) to GMEC overexpressing both isoforms upregulated the expression of LPL and CD36, which help control uptake of long-chain fatty acids into mammary cells. Other responses to ROSI addition to GMEC overexpressing PPARG1 and PPARG2 included upregulation of AGPAT6, DGAT1, INSIG1, SREBF1, and NR1H3. Although the data suggest that both PPARG1 and PPARG2 could affect mammary lipogenesis via control of gene expression when stimulated (e.g., by ROSI), the fact that PPARG1 is more abundant in mammary tissue and that its overexpression alone upregulated key lipogenic gene networks suggest that it is the more important isoform in goat mammary cells.