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CD38/ADP-ribosyl cyclase: A new role in the regulation of osteoclastic bone resorption.

Sun L, Adebanjo OA, Moonga BS, Corisdeo S, Anandatheerthavarada HK, Biswas G, Arakawa T, Hakeda Y, Koval A, Sodam B, Bevis PJ, Moser AJ, Lai FA, Epstein S, Troen BR, Kumegawa M, Zaidi M - J. Cell Biol. (1999)

Bottom Line: We then examined the effects of CD38 on osteoclast function.IL-6, in turn, enhanced CD38 mRNA expression.Taken together, the results provide compelling evidence for a new role for CD38/ADP-ribosyl cyclase in the control of bone resorption, most likely exerted via cADPr.

View Article: PubMed Central - PubMed

Affiliation: Center for Osteoporosis and Skeletal Aging, Department of Medicine, Medical College of Pennsylvania and Veterans Affairs Medical Center, Philadelphia, Pennsylvania 19104, USA.

ABSTRACT
The multifunctional ADP-ribosyl cyclase, CD38, catalyzes the cyclization of NAD(+) to cyclic ADP-ribose (cADPr). The latter gates Ca(2+) release through microsomal membrane-resident ryanodine receptors (RyRs). We first cloned and sequenced full-length CD38 cDNA from a rabbit osteoclast cDNA library. The predicted amino acid sequence displayed 59, 59, and 50% similarity, respectively, to the mouse, rat, and human CD38. In situ RT-PCR revealed intense cytoplasmic staining of osteoclasts, confirming CD38 mRNA expression. Both confocal microscopy and Western blotting confirmed the plasma membrane localization of the CD38 protein. The ADP-ribosyl cyclase activity of osteoclastic CD38 was next demonstrated by its ability to cyclize the NAD(+) surrogate, NGD(+), to its fluorescent derivative cGDP-ribose. We then examined the effects of CD38 on osteoclast function. CD38 activation by an agonist antibody (A10) in the presence of substrate (NAD(+)) triggered a cytosolic Ca(2+) signal. Both ryanodine receptor modulators, ryanodine, and caffeine, markedly attenuated this cytosolic Ca(2+) change. Furthermore, the anti-CD38 agonist antibody expectedly inhibited bone resorption in the pit assay and elevated interleukin-6 (IL-6) secretion. IL-6, in turn, enhanced CD38 mRNA expression. Taken together, the results provide compelling evidence for a new role for CD38/ADP-ribosyl cyclase in the control of bone resorption, most likely exerted via cADPr.

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Related in: MedlinePlus

Effect of the agonist anti-CD38 antibody (A10, 1:5,000 or 1:500) in the presence of substrate (1 mM NAD+) on bone resorption (a, pits per slice) and osteoclast number (b, osteoclasts per slice) as assessed in the pit assay, as well as on supernatant interleukin-6 (IL-6, ng/liter) levels (c) measured by ELISA. P values as indicated (n = 10 slices per group).
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Figure 9: Effect of the agonist anti-CD38 antibody (A10, 1:5,000 or 1:500) in the presence of substrate (1 mM NAD+) on bone resorption (a, pits per slice) and osteoclast number (b, osteoclasts per slice) as assessed in the pit assay, as well as on supernatant interleukin-6 (IL-6, ng/liter) levels (c) measured by ELISA. P values as indicated (n = 10 slices per group).

Mentions: We have shown that while a cytosolic Ca2+ change triggers resorption inhibition, it elevates IL-6 synthesis and release (Zaidi et al. 1989, Moonga et al. 1990, Adebanjo et al. 1998). Our goal, therefore, was to examine the effect of CD38 activation by NAD+ (in the presence of its agonist antibody, A10) on bone resorption and IL-6 release. In the presence of A10, at either dilutions (1:5,000 or 1:500), 1 mM NAD+ inhibited osteoclastic bone resorption significantly (P = 0.034 and P = 0.025, respectively, compared with vehicle-treated cells) (Fig. 9 a). Expectedly, osteoclast number per slice did not change significantly (P > 0.05 for either antibody dilution) (Fig. 9 b), excluding an effect of the antibody on osteoclast formation or demise. In separate experiments, the 1 mM NAD+ (in the presence of A10, 1:500), caused a dramatic and highly significant threefold elevation (P < 0.001) of IL-6 release (Fig. 9 c). Taken together, the results appear consistent with the paradoxical effects of Ca2+ on bone resorption and IL-6 release (Moonga et al. 1990; Adebanjo et al. 1998).


CD38/ADP-ribosyl cyclase: A new role in the regulation of osteoclastic bone resorption.

Sun L, Adebanjo OA, Moonga BS, Corisdeo S, Anandatheerthavarada HK, Biswas G, Arakawa T, Hakeda Y, Koval A, Sodam B, Bevis PJ, Moser AJ, Lai FA, Epstein S, Troen BR, Kumegawa M, Zaidi M - J. Cell Biol. (1999)

Effect of the agonist anti-CD38 antibody (A10, 1:5,000 or 1:500) in the presence of substrate (1 mM NAD+) on bone resorption (a, pits per slice) and osteoclast number (b, osteoclasts per slice) as assessed in the pit assay, as well as on supernatant interleukin-6 (IL-6, ng/liter) levels (c) measured by ELISA. P values as indicated (n = 10 slices per group).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2169484&req=5

Figure 9: Effect of the agonist anti-CD38 antibody (A10, 1:5,000 or 1:500) in the presence of substrate (1 mM NAD+) on bone resorption (a, pits per slice) and osteoclast number (b, osteoclasts per slice) as assessed in the pit assay, as well as on supernatant interleukin-6 (IL-6, ng/liter) levels (c) measured by ELISA. P values as indicated (n = 10 slices per group).
Mentions: We have shown that while a cytosolic Ca2+ change triggers resorption inhibition, it elevates IL-6 synthesis and release (Zaidi et al. 1989, Moonga et al. 1990, Adebanjo et al. 1998). Our goal, therefore, was to examine the effect of CD38 activation by NAD+ (in the presence of its agonist antibody, A10) on bone resorption and IL-6 release. In the presence of A10, at either dilutions (1:5,000 or 1:500), 1 mM NAD+ inhibited osteoclastic bone resorption significantly (P = 0.034 and P = 0.025, respectively, compared with vehicle-treated cells) (Fig. 9 a). Expectedly, osteoclast number per slice did not change significantly (P > 0.05 for either antibody dilution) (Fig. 9 b), excluding an effect of the antibody on osteoclast formation or demise. In separate experiments, the 1 mM NAD+ (in the presence of A10, 1:500), caused a dramatic and highly significant threefold elevation (P < 0.001) of IL-6 release (Fig. 9 c). Taken together, the results appear consistent with the paradoxical effects of Ca2+ on bone resorption and IL-6 release (Moonga et al. 1990; Adebanjo et al. 1998).

Bottom Line: We then examined the effects of CD38 on osteoclast function.IL-6, in turn, enhanced CD38 mRNA expression.Taken together, the results provide compelling evidence for a new role for CD38/ADP-ribosyl cyclase in the control of bone resorption, most likely exerted via cADPr.

View Article: PubMed Central - PubMed

Affiliation: Center for Osteoporosis and Skeletal Aging, Department of Medicine, Medical College of Pennsylvania and Veterans Affairs Medical Center, Philadelphia, Pennsylvania 19104, USA.

ABSTRACT
The multifunctional ADP-ribosyl cyclase, CD38, catalyzes the cyclization of NAD(+) to cyclic ADP-ribose (cADPr). The latter gates Ca(2+) release through microsomal membrane-resident ryanodine receptors (RyRs). We first cloned and sequenced full-length CD38 cDNA from a rabbit osteoclast cDNA library. The predicted amino acid sequence displayed 59, 59, and 50% similarity, respectively, to the mouse, rat, and human CD38. In situ RT-PCR revealed intense cytoplasmic staining of osteoclasts, confirming CD38 mRNA expression. Both confocal microscopy and Western blotting confirmed the plasma membrane localization of the CD38 protein. The ADP-ribosyl cyclase activity of osteoclastic CD38 was next demonstrated by its ability to cyclize the NAD(+) surrogate, NGD(+), to its fluorescent derivative cGDP-ribose. We then examined the effects of CD38 on osteoclast function. CD38 activation by an agonist antibody (A10) in the presence of substrate (NAD(+)) triggered a cytosolic Ca(2+) signal. Both ryanodine receptor modulators, ryanodine, and caffeine, markedly attenuated this cytosolic Ca(2+) change. Furthermore, the anti-CD38 agonist antibody expectedly inhibited bone resorption in the pit assay and elevated interleukin-6 (IL-6) secretion. IL-6, in turn, enhanced CD38 mRNA expression. Taken together, the results provide compelling evidence for a new role for CD38/ADP-ribosyl cyclase in the control of bone resorption, most likely exerted via cADPr.

Show MeSH
Related in: MedlinePlus