Dietary Restriction during Development Enlarges Intestinal and Hypodermal Lipid Droplets in Caenorhabditis elegans

Abstract

Dietary restriction (DR) extends lifespan in man species and modulates evolutionary conserved signalling and metabolic pathways. Most of these studies were done in adult animals. Here we investigated fat phenotypes of C. elegans larvae and adults which were exposed to DR during development. This approach was named “developmental-DR” (dDR). Moderate as well as stringent dDR increased the triglyceride to protein ratio in L4 larvae and adult worms. This alteration was accompanied by a marked expansion of intestinal and hypodermal lipid droplets. In comparison to ad libitum condition, the relative proportion of fat stored in large lipid droplets (>50 µm3) was increased by a factor of about 5 to 6 in larvae exposed to dDR. Microarray-based expression profiling identified several dDR-regulated genes of lipolysis and lipogenesis which may contribute to the observed fat phenotypes. In conclusion, dDR increases the triglyceride to protein ratio, enlarges lipid droplets and alters the expression of genes functioning in lipid metabolism in C. elegans. These changes might be an effective adaptation to conserve fat stores in animals subjected to limiting food supply during development.

S-Adenosyl methionine synthetase 1 limits fat storage in Caenorhabditis elegans

“…It has been shown in both C. elegans and other species that DR increases lifespan, reduces body size and fertility, enlarges LDs, and protects against proteotoxicity (Palgunow et al 2012;Greer and Brunet 2009). Interestingly, these phenotypes have also been observed in SAMS-1-deficient organisms, as shown here and in other studies (Ching et al 2010;Hansen et al 2005;Li et al 2011;Steinkraus et al 2008;Tamiya et al 2013;Walker et al 2011).…”

“…Lipids were extracted through methyl-tertbutyl ether (MTBE) extraction according to the protocol of Matyash et al (Matyash et al 2008). The modified protocol applied for thin-layer chromatography analysis of C. elegans lipid extracts was recently reported by our group (Palgunow et al 2012). Briefly, the samples and standards were loaded onto Polygram silica gel G precoated TLC sheets.…”

The Intestinal Copper Exporter CUA-1 Is Required for Systemic Copper Homeostasis in Caenorhabditis elegans

“…When CUA-1.1 is highly expressed in the hypodermis under dietary copper restriction, most CUA-1.1 localizes to plasma membranes. Notably, the hypodermis is known to act as a major fat storage site in worms by accumulation of lipid droplets (50,51).…”

Gait-specific adaptation of locomotor activity in response to dietary restriction inCaenorhabditis elegans

“…Because several DR techniques have been established in C. elegans (Hara et al, 1998), it is important to note that our protocol is a modified solid medium-based DR protocol. This method (Palgunow et al, 2012) allows standardised reduction of bacterial food during development without starvation, dauer formation or growth arrest. As our method is based on the exclusion of peptone and serial dilution of living E. coli, possible side effects of antibiotics or heat treatment can be excluded.…”

“…The applied DR protocol was recently developed in our laboratory and allows a standardised variation of the extent of DR without starvation, dauer formation or arrest of the animals during development (Palgunow et al, 2012). To analyse the effect of increasing DR conditions, photometrically adjusted optical densities (250 μl, OD 600nm =0.7 to 12.0, represents DR 0.7 to 12.0) of the E. coli strain OP50 were spread onto antibiotic-free NGM agar plates lacking bactopeptone as the sole carbon source for bacterial growth.…”