Differentiating agents regulate cathepsin B gene expression in HL‐60 cells

We utilized HL‐60 cells as a model system to examine the regulation of ctsb gene expression by differentiating agents. Inducers of monocytic differentiation [phorbol ester (PMA), calcitriol (D3), and sodium butyrate (NaB)] and inducers of granulocytic differentiation [all‐trans retinoic acid (RA) and 9‐cis retinoic acid (9‐cis RA)] increase ctsb mRNA levels in a dose‐dependent manner as determined by Northern blot hybridization. D3 and retinoids exert additive effects, suggesting that these agents act in part through distinct pathways. Actinomycin D decay experiments indicate that D3, NaB, RA, and 9‐cis RA do not alter mRNA stability. In contrast, PMA markedly increases the half‐life of ctsb mRNA. In transient transfection assays, PMA and NaB both stimulate transcription of the luciferase reporter gene placed under the control of ctsb promoter fragments. Thus, inducers of HL‐60 cell differentiation can regulate the expression of the ctsb gene at both transcriptional and posttranscriptional levels. J. Leukoc. Biol. 66: 609–616; 1999.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142263/1/jlb0609.pd

Resveratrol: Effects on Lipids and Cardiovascular Risk

For several decades, there has been increasing interest in the possible use of resveratrol as a preventative agent in cardiovascular disease. Resveratrol exerts numerous effects on adipocyte, hepatocyte, and endothelial cell development and function. Many investigations have demonstrated the ability of resveratrol to regulate the adipocyte lifecycle, lipid synthesis, and improve hepatic lipid metabolism. Resveratrol has numerous vascular protective effects on endothelial tissue, including its antiplatelet activity. Resveratrol also reduces intracellular oxidative stress. Animal models of obesity and cardiovascular diseases have yielded important contributions to our understanding of the effects of resveratrol on the vasculature and the risk for pathology. In limited human studies, resveratrol reduces the release of proinflammatory cytokines and improves systemic glucose and insulin regulation and decreases cellular oxidative stress. Therefore, resveratrol has significant potential as both a prophylactic and treatment agent. However additional studies are required to more completely characterize its impacts on human physiology and its benefits in the setting of disease

Cell and Molecular Aging

Discussions of aging invariably begin by establishing a satisfactory definition for the term aging and the related word senescence. Although the term aging is commonly used to refer to postmaturational processes that lead to diminished homeostasis and increased organismic vulnerability, the more correct term for this is senescence (derived from the Latin word “senescere,” meaning to grow old or to diminish), which explicitly refers to the process of growing old and sustaining related deterioration. Aging on the other hand can refer to any time-related process. We will use senescence to refer to cellular phenomena and aging to refer to changes, as organisms grow old

Cellular and Molecular Aging

As a clinical researcher whose area of expertise is Geriatric Pelvic Medicine, the physical changes that go along with increasing age is incredibly interesting to me. However, from a more practical perspective, the biology of aging, although fascinating, is not something that I would be pushed to address in a routine clinical or administrative situation. All that notwithstanding, questions, presumptions, and theories surrounding the definition of aging are inescapable. In fact, more often than I like to admit, I will find myself getting side tracked and drifting off into deep thought about what “aging really means,” or what patients do I consider “old”? Are they really “old”? Which ones might I consider “young” and compare my assessments to their actual chronological age in years? Perhaps, the most frustrating piece of all, is that, almost invariably, after I come out of my intensely contemplative trance on” “aging,” that I end up with more questions than answers

Emerging therapies to treat frailty syndrome in the elderly

Frailty syndrome (FS) has become increasingly recognized as a major predictor of co-morbidities and mortality in older individuals. Interventions with the potential to benefit frail elders include nutritional supplementation (vitamins D, carotenoids, creatine, dehydroepiandrosterone (DHEA), and beta-hydroxy-beta-methylbutyrate) and exercise modalities (tai chi and cobblestone walking). While these have not been explicitly tested for their impact on FS, vitamin D supplementation appears to offer significant promise in enhancing long-term health of the elderly. Exercise modalities such as tai chi and cobblestone walking, because of probable low risk and ease of participation, may also confer benefit. Additional studies are needed to investigate interventions that directly prevent, delay, and/or ameliorate frailty. Successful therapies may well involve multi-component approaches utilizing a combination of medication, nutritional supplementation, and exercise

Retinoic acid inhibits NFATc1 expression and osteoclast differentiation

Ingestion of excess vitamin A appears to correlate with an increased fracture risk, an outcome that is likely mediated by retinoic acids (RAs); these are vitamin A metabolites that have dramatic effects on skeletal development. We studied the impacts of RA and isoform-specific RA receptor (RAR) agonists (α, β, and γ) on osteoclast formation (osteoclastogenesis) in two model systems: RAW264.7 cells and murine bone marrow-derived monocytes. The pan-RAR agonists, all-trans and 9-cis RA, inhibited receptor activator of nuclear factor kappa B ligand (RANKL)-mediated osteoclast differentiation in a concentration-dependent manner. Isoform-specific RAR agonists (α, β, and γ) also inhibited osteoclastogenesis, with the RARα agonist producing the most consistent reductions in both osteoclast number and size and total area covered. Inhibition of osteoclastogenesis correlated with reductions in expression, DNA binding, and nuclear abundance of nuclear factor of activated T cells c1 (NFATc1), a transcription factor critical for osteoclastogenesis. The upregulation of three NFATc1-responsive genes, cathepsin K, dendritic cell-specific transmembrane protein and osteoclast-associated receptor were similarly reduced following RA or RAR agonist exposure. These results suggest that RA blocks in vitro RANKL-mediated osteoclastogenesis by decreasing NFATc1 function