A Mechanistic Study of the Antiaging Effect of Raw-Milk Cheese Extracts

Abstract

Many studies have highlighted the relationship between food and health status, with the aim of improving both disease prevention and life expectancy. Among the different food groups, fermented foods a have huge microbial biodiversity, making them an interesting source of metabolites that could exhibit health benefits. Our previous study highlighted the capacity of raw goat milk cheese, and some of the extracts recovered by the means of chemical fractionation, to increase the longevity of the nematode Caenorhabditis elegans. In this article, we pursued the investigation with a view toward understanding the biological mechanisms involved in this phenomenon. Using mutant nematode strains, we evaluated the implication of the insulin-like DAF-2/DAF-16 and the p38 MAPK pathways in the phenomenon of increased longevity and oxidative-stress resistance mechanisms. Our results demonstrated that freeze-dried raw goat milk cheese, and its extracts, induced the activation of the DAF-2/DAF-16 pathway, increasing longevity. Concerning oxidative-stress resistance, all the extracts increased the survival of the worms, but no evidence of the implication of both of the pathways was highlighted, except for the cheese-lipid extract that did seem to require both pathways to improve the survival rate. Simultaneously, the cheese-lipid extract and the dried extract W70, obtained with water, were able to reduce the reactive oxygen species (ROS) production in human leukocytes. This result is in good correlation with the results obtained with the nematode.

Exploring the Impact of French Raw-Milk Cheeses on Oxidative Process Using Caenorhabditis elegans and Human Leukocyte Models

“…An agar medium (per L: 3 g of NaCl and 6 g of agarose) was prepared and stored at 40 °C as previously described [ 32 ]. The medium was then split into aliquots, individually supplemented with 1% of cheese fraction ( w / v ).…”

“…The effect of the cheese fractions (FDC, ApE, W40, and W70) on the survival of C. elegans on an oxidative medium was determined as described in the previous study [ 32 ]. After 5 days of incubation on the NME plate, ≈15 worms per well were transferred onto an agar medium (per L: 3 g of NaCl and 6 g of agarose; “Free condition”) or with hydrogen peroxide (final concentration 3 mM; “H 2 O 2 condition”) for 3.5 h.…”

“…Quantitative Analyses of the daf-16, skn-1, ctl-2, and sod-3 Gene Expression in Caenorhabditis elegans L4-synchronized worms were cultivated for 5 days on NME plates supplemented or not with FDC (1%, w/v) and then exposed for one hour to M9 buffer with H 2 O 2 (final concentration 0.75 mM) at slow agitation and room temperature. The mRNA expression levels of two transcription factors (daf-16 and skn-1) and two antioxidant enzymes (ctl-2 and sod-3) were measured quantitatively by real-time PCR after this exposure, following the protocol previously described [32]. Worms were collected and washed twice with M9 buffer.…”

“…France is an important cheese production area, but few studies have been conducted to estimate the antioxidant activities of French raw-milk cheese using human cell cultures or animal models. One of our previous studies demonstrated that raw goat milk cheese (the entire cheese and cheese extracts) increased, at the same time, the capacity of the nematode Caenorhabditis elegans ( C. elegans ) to survive on an oxidative medium and decreased ROS production by human cells [ 32 ]. The similarities between C. elegans and human genetics, the conservation of the antioxidative response’s metabolic pathways, and the transparency of the body’s nematode make it a reliable experimental model to test the impact of such cheese fractions on the host [ 33 ].…”

A clustering-based survival comparison procedure designed to study the Caenorhabditis elegans Model

“…In the same time interval, we reference 96,488 publications with the keyword lifespan, including 4,702 for the worm. The nematode has been used in a large number of elds including aging [11], immunity [12], abiotic stresses like oxidative stress [13], hypoxia [14], heat stress [15], cold tolerance [16], osmotic stress [17], UV light [18], heavy metal stress [19] and biotic stress (pathogenic bacteria [20] and fungi [21]), toxicity testing [22] and the measurement of lifespan is very often used. It is a setting widely used in biology to visualize the effect of a treatment on an organism.…”