PMID- 35210514 OWN - NLM STAT- MEDLINE DCOM- 20220321 LR - 20220321 IS - 2045-2322 (Electronic) IS - 2045-2322 (Linking) VI - 12 IP - 1 DP - 2022 Feb 24 TI - Loss of chaperone-mediated autophagy is associated with low vertebral cancellous bone mass. PG - 3134 LID - 10.1038/s41598-022-07157-9 [doi] LID - 3134 AB - Chaperone-mediated autophagy (CMA) is a protein degradation pathway that eliminates soluble cytoplasmic proteins that are damaged, incorrectly folded, or targeted for selective proteome remodeling. However, the role of CMA in skeletal homeostasis under physiological and pathophysiological conditions is unknown. To address the role of CMA for skeletal homeostasis, we deleted an essential component of the CMA process, namely Lamp2a, from the mouse genome. CRISPR-Cas9-based genome editing led to the deletion of both Lamp2a and Lamp2c, another Lamp2 isoform, producing Lamp2AC global knockout (L2ACgKO) mice. At 5 weeks of age female L2ACgKO mice had lower vertebral cancellous bone mass compared to wild-type (WT) controls, whereas there was no difference between genotypes in male mice at this age. The low bone mass of L2ACgKO mice was associated with elevated RANKL expression and the osteoclast marker genes Trap and Cathepsin K. At 18 weeks of age, both male and female L2ACgKO mice had lower vertebral cancellous bone mass compared to WT controls. The low bone mass of L2ACgKO mice was associated with increased osteoclastogenesis and decreased mineral deposition in cultured cells. Consistent with these findings, specific knockdown of Lamp2a in an osteoblastic cell line increased RANKL expression and decreased mineral deposition. Moreover, similar to what has been observed in other cell types, macroautophagy and proteasomal degradation were upregulated in CMA-deficient osteoblasts in culture. Thus, an increase in other protein degradation pathways may partially compensate for the loss of CMA in osteoblasts. Taken together, our results suggest that CMA plays a role in vertebral cancellous bone mass accrual in young adult mice and that this may be due to an inhibitory role of CMA on osteoclastogenesis or a positive role of CMA in osteoblast formation or function. CI - (c) 2022. The Author(s). FAU - Akel, Nisreen AU - Akel N AD - Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA. FAU - MacLeod, Ryan S AU - MacLeod RS AD - Center for Musculoskeletal Disease Research, University of Arkansas for Medical Sciences, Little Rock, AR, USA. AD - Division of Endocrinology, University of Arkansas for Medical Sciences, Little Rock, AR, USA. FAU - Berryhill, Stuart B AU - Berryhill SB AD - Bone Biomechanics, Histology and Imaging Core (BHIC), University of Arkansas for Medical Sciences, Little Rock, AR, USA. FAU - Laster, Dominique J AU - Laster DJ AD - Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA. FAU - Dimori, Milena AU - Dimori M AD - Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA. FAU - Crawford, Julie A AU - Crawford JA AD - Bone Biomechanics, Histology and Imaging Core (BHIC), University of Arkansas for Medical Sciences, Little Rock, AR, USA. FAU - Fu, Qiang AU - Fu Q AD - Center for Musculoskeletal Disease Research, University of Arkansas for Medical Sciences, Little Rock, AR, USA. AD - Genetic Models Core, University of Arkansas for Medical Sciences, Little Rock, AR, USA. FAU - Onal, Melda AU - Onal M AD - Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA. monal@uams.edu. LA - eng GR - P20 GM125503/GM/NIGMS NIH HHS/United States GR - P20GM125503/GM/NIGMS NIH HHS/United States PT - Journal Article PT - Research Support, N.I.H., Extramural PT - Research Support, Non-U.S. Gov't DEP - 20220224 PL - England TA - Sci Rep JT - Scientific reports JID - 101563288 RN - 0 (Lysosomal-Associated Membrane Protein 2) RN - 0 (Molecular Chaperones) SB - IM MH - Animals MH - *Autophagy MH - Calcification, Physiologic MH - Cancellous Bone/*metabolism MH - Female MH - Lysosomal-Associated Membrane Protein 2/*genetics/metabolism MH - Male MH - Mice MH - Mice, Knockout MH - Molecular Chaperones/*genetics/metabolism MH - Organ Size MH - Osteoclasts/*metabolism MH - Spine/*metabolism PMC - PMC8873216 COIS- The authors declare no competing interests. EDAT- 2022/02/26 06:00 MHDA- 2022/03/22 06:00 PMCR- 2022/02/24 CRDT- 2022/02/25 05:34 PHST- 2021/05/11 00:00 [received] PHST- 2022/02/07 00:00 [accepted] PHST- 2022/02/25 05:34 [entrez] PHST- 2022/02/26 06:00 [pubmed] PHST- 2022/03/22 06:00 [medline] PHST- 2022/02/24 00:00 [pmc-release] AID - 10.1038/s41598-022-07157-9 [pii] AID - 7157 [pii] AID - 10.1038/s41598-022-07157-9 [doi] PST - epublish SO - Sci Rep. 2022 Feb 24;12(1):3134. doi: 10.1038/s41598-022-07157-9.