miR-93/Sp7 function loop mediates osteoblast mineralization

Abstract

microRNAs (miRNAs) play pivotal roles in osteoblast differentiation. However, the mechanisms of miRNAs regulating osteoblast mineralization still need further investigation. Here, we performed miRNA profiling and identified that miR-93 was the most significantly downregulated miRNA during osteoblast mineralization. Overexpression of miR-93 in cultured primary mouse osteoblasts attenuated osteoblast mineralization. Expression of the Sp7 transcription factor 7 (Sp7, Osterix), a zinc finger transcription factor and critical regulator of osteoblast mineralization, was found to be inversely correlated with miR-93. Then Sp7 was confirmed to be a target of miR-93. Overexpression of miR-93 in cultured osteoblasts reduced Sp7 protein expression without affecting its mRNA level. Luciferase reporter assay showed that miR-93 directly targeted Sp7 by specifically binding to the target coding sequence region (CDS) of Sp7. Experiments such as electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation (ChIP), and promoter luciferase reporter assay confirmed that Sp7 bound to the promoter of miR-93. Furthermore, overexpression of Sp7 reduced miR-93 transcription, whereas blocking the expression of Sp7 promoted miR-93 transcription. Our study showed that miR-93 was an important regulator in osteoblast mineralization and miR-93 carried out its function through a novel miR-93/Sp7 regulatory feedback loop. Our findings provide new insights into the roles of miRNAs in osteoblast mineralization. ß

miR-450a-5p within rat adipose tissue exosome-like vesicles promotes adipogenic differentiation by targeting WISP2

“…miR-125b-5p, miR-30e-3p and miR-204-5p), whereas several of them (e.g. miR-93-5p and miR-203-3p) had been reported to negatively regulate osteogenesis (Table S3) (Kennell et al, 2008;Hamam et al, 2014;Yang et al, 2012;. Eguchi et al also analyzed the miRNAs in adipocytes derived from EVs and detected several adipogenic miRNAs (including miR-148a-3p, miR-181a-5p, miR30a-5p, miR-125b-5p) (Eguchi et al, 2016), which is consistent with our results (Table S3).…”

miR-148a regulates osteoclastogenesis by targeting V-maf musculoaponeurotic fibrosarcoma oncogene homolog B

“…miRNAs play a key role in various biological processes including osteoblast differentiation and mineralization. (29)(30)(31) Osteoclastogenesis is also regulated by miRNAs. In the present study, we performed microarray assays and found miR-148a dramatically upregulated during osteoclast differentiation.…”

Epigenetic Aspects of Osteoporosis

“…В определенной степени, остерикс (OSX) -транс-крипционный фактор, необходимый для формирования костной ткани, находится под контролем мкРНК, образуя уникальную ауторегуляторную петлю обратной связи с мкРНК93. мкРНК93 ингибирует минерализацию, воз-действуя на OSX [47]. Wnt-сигнальный путь также нахо-дится под контролем определенных мкРНК.…”

“…Таргетная молекула Источник мкРНК, стимулирующие дифференцировку остеобластов мкРНК27, микроРНК142-3p APC [51,52] мкРНК29a Дкк1, KREMEN2, сФРЗ2, SPARC [48,54] мкРНК29b COL1A1, COL5A3, COL4A2, HDAC4, ТФРβ3, ACVR2A, CTNNBIP1, DUSP2 [55] мкРНК218 SOST, Дкк2, сФРЗ2 [49] мкРНК335-5p Дкк1 [50] мкРНК, блокирующие дифференцировку остеобластов мкРНК23a RUNX2, SATB2 [37,43,44] мкРНК30a-d RUNX2, SMAD1 [38,43,44] мкРНК34c, мкРНК133a, мкРНК137, мкРНК204, мкРНК205, мкРНК211, мкРНК217, мкРНК335, мкРНК338, мкРНК433, мкРНК3077-5p RUNX2 [39][40][41][42][43][44]53] мкРНК93 OSX [47] мкРНК135a RUNX2, SMAD5 [39,43,44] мкРНК155 SOCS1 [56] Примечание. APC -аденоматозная полипозная палочка; Дкк1 и 2 -Диккопф 1 и 2; KREMEN2 -кринглсодержащий трансмембран-ный белок; сФРЗ2 -секреторный белок, связанный с фризельдом 2; SPARC -секретируемый белок, кислый, богатый цистеином (остеонектин); COL1A1 -коллаген, тип I, α 1; COL5A3 -коллаген, тип V, α 3; COL4A2 -коллаген, тип IV, α 2; HDAC4 -гистонде-ацетилаза 4; ТФРβ 3 -трансформирующий фактор роста β 3 ; ACVR2A -рецептор типа 2А к активину А; CTNNBIP1 -белок, взаимо-действующий с β-катенином, 1; DUSP2 -фосфатаза двойной специфичности, тип 2; SOST -склеростин; RUNX2 -фактор транс-крипции 2, содержащий домен Runt; SATB2 -ДНК-связывающий белок; SMAD1 и 5 -семейство SMAD тип 1 и 5; OSX -остерикс; SOCS1 -супрессор цитокиновых сигналов 1.…”