Cardiovascular diseases, or CVDs, are collectively the most notorious gang of cold-blooded killers threatening human lives today. These unforgiving villains, including the likes of coronary heart disease, cerebrovascular disease and pulmonary embolisms, are jointly responsible for more deaths per year than any other source, securing their seat as the number one cause of human mortality on a global scale.
One of the
trademarks of most CVDs is the thickening and stiffening of the arteries, a
condition known as atherosclerosis. Atherosclerosis is characterized by the
accumulation of cholesterol, fats and other substances, which together form
plaques in and on the artery walls. These plaques clog or narrow your arteries
until they completely block the flow of blood, and can no longer supply
sufficient blood to your tissues and organs. Or the plaques can burst, setting
off a disastrous chain reaction that begins with a blood clot, and often ends
with a heart attack or stroke.
Given the global prevalence and magnitude of this problem, there is a significant and urgent demand for better ways to treat CVDs. In a recent study published in Nature Communications, researchers at the Carnegie Institution for Science, Johns Hopkins University and Mayo Clinic are taking the fight to CVDs through the study of low-density lipoproteins (LDLs), the particles responsible for shuttling bad cholesterol throughout the bloodstream.
RNA molecules have become a hot topic of research. While I was taught about messenger RNA (mRNA), ribosomal RNA (rRNA) and transfer RNA (tRNA), many more varieties have come into the nomenclature after I graduated with my science degrees. Even more interesting, these RNAs do not code for a protein, but instead have a role in regulating gene expression. From long non-coding RNA (lncRNA) to short interfering RNA (siRNA), microRNA (miRNA) and small nucleolar RNA (snoRNA), these classes of RNAs affect protein translation, whether by hindering ribosomal binding, targeting mRNA for degradation or even modifying DNA (e.g., methylation). This post will cover the topic of microRNAs, explaining what they are, how researchers understand their function and role in metabolism, cancer and cardiovascular disease, and some of the challenges in miRNA research.
What are microRNAs? MicroRNAs (miRNAs) are short noncoding RNAs 19–25 nucleotides long that play a role in protein expression by regulating translation initiation and degrading mRNA. miRNAs are coded as genes in DNA and transcribed by RNA polymerase as a primary transcript (pri-miRNA) that is hundreds or thousands of nucleotides long. After processing with a double-stranded RNA-specific nuclease, a 70–100 nucleotide hairpin RNA precursor (pre-miRNA) is generated and transported from the nucleus into the cytoplasm. Once in the cytoplasm, the pre-miRNA is cleaved into an 18- to 24-nucleotide duplex by ribonuclease III (Dicer). This cleaved duplex associates with the RNA-induced silencing complex (RISC), and one strand of the miRNA duplex remains with RISC to become the mature miRNA. Continue reading “microRNA: The Small Molecule with a Big Story”
Adversity and stress are known risk factors for psychiatric disorders, cardiovascular and immune disease, cognitive decline and other health problems. The long-term negative effects of adversity seem to be greatest if the traumatic events were experienced during childhood, when the brain and other biological systems are developing and maturing. Researchers are working to identify the mechanisms involved and have identified telomere shortening as one possible mechanism by which adversity increases morbidity and mortality. Continue reading “The Link Between Childhood Adversity and Cellular Aging”
As someone who regularly works at a computer both at work and at home, sedentary activity is a part of my daily life. Unfortunately, my desk is the standard kind that requires me to sit on a chair; I can only dream of the kind that has a treadmill to encourage movement as I work. The health consequences of sitting for long periods of time have been covered in research papers and other blogs, but a recent paper highlighted how it is not only how long we are sedentary but how often we step away from our desks and sofas that affects our health. Continue reading “Stand Up and Walk; Repeat Often”