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Cytoplasmic serine/threonine Pim kinases have emerged as important modulators of immune regulation and oncology. However, their regulatory roles in bone remodeling remain obscure. Here, we aimed to determine the roles of Pim kinases in periodontal disease (PD), focusing on the regulation of osteoclastogenesis and bone resorptive activity. We investigated Pim kinases expression in PD by analyzing data from the online Gene Expression Omnibus database and using ligature-induced periodontitis mouse model. The expression of Pim kinases during receptor activator of nuclear factor kB ligand (RANKL)-induced osteoclastogenesis was assessed in mouse bone marrow-derived macrophages (BMMs) using reverse transcription polymerase chain reaction. Osteoclast differentiation and bone resorption activity were respectively verified by tartrate-resistant acid phosphatase staining and dentin disc-based bone resorption assays. We silenced and overexpressed Pim-2 using small interfering RNA (siRNA) and retroviral vector, respectively, to investigate the molecular mechanisms underlying Pim-2 regulation in RANKL-induced osteoclastogenesis and bone resorption activity. Upregulated expression of Pim-2 was observed in both patients with PD and periodontitis-affected mouse gingival tissues. siRNA-mediated silencing of Pim-2 in BMMs diminished RANKL-induced resorptive activity without affecting osteoclastogenesis. Moreover, RANKL-triggered stimulation of a3 isoform, which is a subunit of vacuolar-type ATPase, was selectively attenuated in BMMs on silencing Pim-2. The overexpression of Pim-2 with a retroviral vector stimulated the a3 subunit, thus inducing bone resorption activity. Taken together, these results suggest that Pim-2 acts as a major modulator of osteoclastic activity by regulating a3 isoform expression in PD.

Osteoporosis is a common systemic skeletal disease that predominantly affects people older than 50 years and often co-occurs with dementia. Studies have been conducted to find out the relation between the two, but this is not well studied in the Vietnamese population. This study aimed to analyze the impact of osteoporosis on the risk of dementia in Vietnamese immigrants. We identified 38(female(F) 26, male(M) 12) community-dwelling Vietnamese patients aged ≥ 55 seen at the cognitive assessment clinic in a community health center 1/2021-8/2021 through chart review. Because either DEXA was not performed or the results were unavailable, 23 patients (F 12, M 11) were excluded. We assigned the patients with normal cognitive tests results or a diagnosis of mild cognitive impairment to the control group and those diagnosed with dementia to the study group. Among 15 patients, 10(F 9, M 1) patients were diagnosed with dementia. Seven patients (F 6, M 1) had osteoporosis. Five patients (F 5) were assigned to the control group, and two patients had osteoporosis. (OR 3.5000, P = 0.2736) The odds of developing dementia were 3.5 higher given osteoporosis diagnosis than with no osteoporosis. These results suggested a positive association between osteoporosis and dementia in Vietnamese immigrants. More studies with a larger number of patients in this cohort are needed to investigate this further. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m., Saturday, June 11, 2022 1:18 p.m. - 1:23 p.m.