Genetic and Behavioral Factors that Impact Obesity

Jennifer Beshel began her lecture by mentioning the rising rate of obesity in the United States which marks obesity as a recognized disease/disorder that needs to be dealt with. She compared statistics from 1990 and it is important to note that levels of obesity in America and the world have skyrocketed. In regards to her research, she goes on to discuss the factors behind food cues and food behaviors in animals that results in an increase in consumption. In her article “"A Leptin Analog Locally Produced in the Brain Acts via a Conserved Neural Circuit to Modulate Obesity-Linked Behaviors in Drosophila” she and other researchers present how the manipulation of the leptin homolog upd1 (unpaired 1) can lead to subjects gaining weight. The upd1 when inhibited causes symptoms of increased food consumption, which is much similar to the way leptin impacts hunger. Subsequently, Beshel uses this research to further investigate the release of leptin and its regulation. Those subjects with inhibited upd1 also expressed higher sensitivity to food cues and much higher attraction to food. This also explains why upd1 knockout subjects gained almost 3x more weight than their wildtype counter parts. Furthermore, the researchers also noted that reduction of upd2 (unpaired 2) within adipose tissues leads to a reduction of bodyweight and size. When exposed to this new knowledge, it is easy to conclude that expression of leptin analogs is paramount to food-related behaviors.

On the other hand, genes are not the only impactors that affect body weight and size. Some of the issues regarding obesity can be attributed to improper food intake behaviors or other chronobiological factors. In the news article titled “Molecular Clocks Scattered throughout Your Body (Not Just in the Brain) Keep Your Tissues Humming” the authors compile research data from multiple studies and imply that the human body itself has multiple clocks spread through different regions of the body. These regions include the liver, pancreas, adipose tissues and many other organs in the human system. Scientists find that insufficient sleep, lack of exercise and poor diet (as seen in many shift workers in America) can affect the peripheral clocks in the body, which in turn leads to a diminished metabolic health which translates to physiological abnormalities such as obesity and other metabolic disorders. Another study mentioned in the article is Mitch Lazar’s manipulation of the clock gene called Re-Verba, which acts as a timer for the enzyme HDAC3. Inhibiting Re-verba lead to diminished amounts of HDAC3, which resulted in a fatty liver, or Hepatic Steatosis. This goes to show interruption of the biological clocks in the body can have negative effects, the same can be said for clock genes in the adipose tissues. Mice lacking intact clocks in adipose tissue cells changed their food intake behavior by eating more during the daytime (leading to obesity). All of this research in conjunction shows that internal body clocks impact feeding behaviors, and it is important to get proper sleep, exercise regularly and have a balanced diet in order to re-align these clocks and maintain proper metabolic health and protect from other disorders.

All in all, both these pieces of research highlight the prevalent issue of obesity in our community. This research should be further investigated in order to combat obesity through proper maintenance of health (sleeping, eating, and exercising appropriately), and to create treatments for those with genetic dispositions. Hopefully we get to see more results from these studies.

Works Cited

Beshel, Jennifer, et al. “A Leptin Analog Locally Produced in the Brain Acts via a Conserved Neural Circuit to Modulate Obesity-Linked Behaviors in Drosophila.” Cell Metabolism, vol. 25, no. 1, 2017, pp. 208–217.

Summa, Keith C. “Molecular Clocks Scattered throughout Your Body (Not Just in the Brain) Keep Your Tissues Humming.” Scientific American, Scientific American , Feb. 2015, https://www.scientificamerican.com/article/molecular-clocks-scattered-throughout-your-body-not-just-in-the-brain-keep-your-tissues-humming/.