The Nicotinamide Adenine Dinucleotide (NAD)-Dependent Deacetylase Sirtuin-1 Regulates Chondrocyte Energy Metabolism through the Modulation of Adenosine Monophosphate-Activated Protein Kinase (AMPK) in Osteoarthritis(OA)

Abstract

To clarify how the osteoarthritis (OA)-induced catabolic factor interleukin (IL)-1β affects chondrocyte energy metabolism, and especially to define the downstream pathway linking nicotinamide adenine dinucleotide (NAD)-dependent deacetylase Sirtuin-1 (Sirt-1) to energy metabolism in OA chondrocytes. Human chondrocytes were isolated from articular cartilage samples of patients with OA. The level of energy metabolism of OA chondrocytes was evaluated by monitoring the activity of the energy metabolic sensor, adenosine monophosphate-activated protein kinase (AMPK) and the level of production of adenosine triphosphate (ATP) in chondrocytes in the presence or absence of t IL-1β (10 ng/mL). Effects of IL-1β on anabolic and catabolic activities of chondrocytes were analyzed by the levels of production of proteoglycan and matrix metalloproteinase (MMP)-13, respectively. Experiments involving pre-treatment with Sirt-1 inhibitor were also performed to investigate the underlying regulatory mechanism linking Sirt-1 to chondrocyte energy metabolism. IL-1β significantly inhibited the activity of AMPK and production of ATP in OA chondrocytes. The energy metabolism disruption mediated by IL-1β was further decreased by pretreatment with Sirt-1 inhibitor in OA chondrocytes. Treatment with IL-1β significantly decreased the level of proteoglycan production and significantly increased the level of MMP-13 secretion by chondrocytes. These chondrocyte activities were also reduced by pre-treatment with the Sirt-1 inhibitor in OA chondrocytes. IL-1β inhibits the AMPK -ATP energy metabolic pathway in OA chondrocytes. Our findings also suggest that Sirt-1 activity is involved in anabolic and catabolic cellular activities and that Sirt-1 modulates ATP production through functional regulation of the energy sensor AMPK in chondrocytes.

SIRT1 directly activates autophagy in human chondrocytes

“…Consequently, metabolic alterations resulting in leading to changes in the NADH/NAD+ ratio, have potential to indirectly impact the range of cellular processes controlled by Sirtuin proteins, such as mitochondrial biogenesis and insulin sensitivity, and which includes SirT1 activity. Interestingly, the loss of SIRT1 and the NAD + co-factor, are shown to be decreased in OA patients and experimental models of bone and joint disease [5][6][7][15][16][17] . Recent observational studies in mice suggest that loss of SIRT1 in all chondrocytes through use of the type II collagen promoter, predisposed to OA development at 1 year 18 .…”

Infrapatellar Fat Pad Stem Cells Responsiveness to Microenvironment in Osteoarthritis: From Morphology to Function

“…Cartilage ECM breakdown products, fibronectin and hyaluronic acid (Okamura et al, 2001;Termeer et al, 2002;van Lent et al, 2012) and intracellular alarmins [HMGB1 (Li et al, 2011), S100 proteins (van Lent et al, 2012)] signal on synovial macrophages, synoviocytes, or chondrocytes promoting the local production of numerous inflammatory mediators [IL-1β (He et al, 2002), VEGF, TNFα, IL-6 (Ushiyama et al, 2003), PDGFs (Pohlers et al, 2006)]. Moreover, regulatory mechanisms involved in controlling NAD + levels have been demonstrated to be affected in OA because of an increased expression of IL-β and a compromised activity of NADases (Kobayashi et al, 2017). Thus, endoplasmic reticulum stress and highly expressed vacuoles in concert with the expression of prognostic OA marker IL-1βR1 highlight the occurrence of a strict correlation between OA-IFP biology and the inflammatory microenvironment (Daheshia and Yao, 2008).…”

Physiologic Mechanical Stress Directly Induces Bone Formation by Activating Glucose Transporter 1 (Glut 1) in Osteoblasts, Inducing Signaling via NAD+-Dependent Deacetylase (Sirtuin 1) and Runt-Related Transcription Factor 2 (Runx2)

“…These findings suggest that mechanical loading increases glucose uptake via an upregulated Glut1 in osteoblasts. This increase in glucose uptake may reduce the activity of the energy sensor SIRT1 as well as AMPK, since SIRT1 is known to crosstalk with AMPK, forming a SIRT1-AMPK positive feedback loop in cellular energy metabolism [23,50,51]. From the results of previous studies, we postulated that the mechanical loading could induce the increased level of Glut-1 and its resultant decreases in both energy sensors, SIRT1 and AMPK.…”

“…Articular cartilage explants were cut into small pieces, washed with PBS, and digested individually with 1.0 mg/mL collagenase type I (#035-17604, Fujifilm Wako Pure Chemical Inc., Tokyo, Japan) in DMEM (Sigma-Aldrich) overnight on a shaking platform at 3 • C. Isolated chondrocytes from each explant were collected following centrifugation; washed three times with PBS; resuspended; and then cultured in DMEM supplemented with 10% heat-inactivated FBS, 2 mM L-glutamine (Sigma-Aldrich), and 100 U/mL each of penicillin and streptomycin (Cosmo Bio) at 3 • C in a humidified atmosphere of 95% air and 5% CO 2 , as previously reported [23,30,57]. A sufficient number of cultured chondrocytes were obtained from the relatively normal parts of surgically resected cartilage tissues.…”

“…To study the effects of mechanical stress on the expressions of Glut1, SIRT1, and Runx2 in each cell strain of osteoblasts and chondrocytes, the expression levels of Glut1, SIRT1, and Runx2 in cells were analyzed by Western blotting as previously described [23,31,57].…”