Differentially expressed proteins identified by TMT proteomics analysis in bone marrow microenvironment of osteoporotic patients

Ultrasound Characterization of Cortical Bone Using Shannon Entropy

OBJECTIVE

Ultrasound backscattered signals encompass information on the microstructure of heterogeneous media such as cortical bone, in which pores act as scatterers and result in the scattering and multiple scattering of ultrasound waves. The objective of this study was to investigate whether Shannon entropy can be exploited to characterize cortical porosity.

METHODS

In the study described here, to demonstrate proof of concept, Shannon entropy was used as a quantitative ultrasound parameter to experimentally evaluate microstructural changes in samples with controlled scatterer concentrations made of a highly absorbing polydimethylsiloxane matrix (PDMS). Similar assessment was then performed using numerical simulations on cortical bone structures with varying average pore diameter (Ct.Po.Dm.), density (Ct.Po.Dn.) and porosity (Ct.Po.).

RESULTS

The results suggest that an increase in pore diameter and porosity lead to an increase in entropy, indicating increased levels of randomness in the signals as a result of increased scattering. The entropy-versus-scatterer volume fraction in PDMS samples indicates an initial increasing trend that slows down as the scatterer concentration increases. High levels of attenuation cause the signal amplitudes and corresponding entropy values to decrease drastically. The same trend is observed when porosity of the bone samples is increased above 15%.

CONCLUSION

Sensitivity of entropy to microstructural changes in highly scattering and absorbing media can potentially be exploited to diagnose and monitor osteoporosis.

Osteoporosis and Alveolar Bone Health in Periodontitis Niche: A Predisposing Factors-Centered Review

Periodontitis is a periodontal inflammatory condition that results from disrupted periodontal host-microbe homeostasis, manifested by the destruction of tooth-supporting structures, especially inflammatory alveolar bone loss. Osteoporosis is characterized by systemic deterioration of bone mass and microarchitecture. The roles of many systemic factors have been identified in the pathogenesis of osteoporosis, including endocrine change, metabolic disorders, health-impaired behaviors and mental stress. The prevalence rate of osteoporotic fracture is in sustained elevation in the past decades. Recent studies suggest that individuals with concomitant osteoporosis are more vulnerable to periodontal impairment. Current reviews of worse periodontal status in the context of osteoporosis are limited, mainly centering on the impacts of menopausal and diabetic osteoporosis on periodontitis. Herein, this review article makes an effort to provide a comprehensive view of the relationship between osteoporosis and periodontitis, with a focus on clarifying how those risk factors in osteoporotic populations modify the alveolar bone homeostasis in the periodontitis niche.

Low Unsaturated Fatty Acids Level in the Vertebral Bone Marrow of Postmenopausal Osteoporosis: A Pilot 2D iDQC‐MRS on 3.0 T Study

BACKGROUND

Unsaturated fatty acids (UFAs) of bone marrow play a critical role in osteoporosis. However, it is difficult to resolve the UFA, especially in the presence of trabecular bone, using conventional magnetic resonance spectroscopy (MRS) methods.

PURPOSE

To preliminarily compare the bone marrow fatty acids (FAs) composition in the presence of trabecular bone of postmenopausal osteoporosis (PMOP) and healthy controls (HC).

STUDY TYPE

Prospective.

SUBJECTS

Total thirty-six postmenopausal women were recruited with CT-confirmed PMOP (n = 19) and HC (n = 17).

FIELD STRENGTH/SEQUENCES

A 3 T scanner. Localized 2D intermolecular double-quantum coherence-based MRS (iDQC-MRS).

ASSESSMENT

In addition to the conventional water and fat peaks, another four crossing peaks of the FAs were well resolved from the L4 vertebral bone marrow using iDQC-MRS technique: allylic methylene (2.0 ppm), terminal methylene (2.2 ppm), diallylic methylene (2.7 ppm), and olefinic (5.3 ppm). The monounsaturated fatty acids (MOFA) and polyunsaturated fatty acids (PUFAs) were then calculated.

STATISTICAL TESTS

Differences between PMOP and HC were investigated using the analysis of a t-test, and the relationships were investigated using regression analysis.

RESULTS

MOFAs and PUFAs fractions were significantly lower in the PMOP group compared to the HC group. In contrast, the saturated FAs fraction is significantly higher in the PMOP group. Additionally, decreased PUFAs, MOFAs were moderately negatively correlated with the volumetric bone mineral density (vBMD) in the PMOP group. Furthermore, increased SFAs in PMOP were strongly associated with vBMD.

DATA CONCLUSION

Using spectra resolution enhanced 2D iDQC-MRS technique, we observed low unsaturated FAs levels in the vertebral bone marrow of the PMOP patients. The reduced unsaturated FAs levels in PMOP may be associated with dysfunction of the balance between osteoblastogenesis and osteoclastogenesis.

LEVEL OF EVIDENCE: 2

TECHNICAL EFFICACY STAGE

1.

Transcriptomic analysis provides a new insight: Oleuropein reverses high glucose-induced osteogenic inhibition in bone marrow mesenchymal stem cells via Wnt10b activation

Adverse events of diabetes mellitus (DM) include bone damages, such as the increased incidence of osteoporosis and bone fractures, which are known as diabetic osteopathy. The pathogenic mechanism of diabetic osteopathy is complex, and hyperglycemia is a vital cause involved in it. Bone marrow mesenchymal stem cells (BMSCs) exert a significant effect on bone formation. Therefore, in this paper, transcriptomic changes of BMSCs cultured in high glucose (35 mM) for 30 days are mainly investigated. In addition, 794 up-regulated genes and 1,162 down-regulated genes were identified. Then, biological functions of the differentially expressed genes in the high glucose microenvironment were investigated by two kinds of functional analyses. Gene Set Enrichment Analysis was also applied to focus on the significant gene sets and it is found that Wnt10b expression witnessed a remarkable decrease in BMSCs under the high glucose microenvironment. At last, in vitro experiments revealed that oleuropein effectively reversed high glucose-induced osteogenic inhibition via activating Wnt10b in BMSCs.

Sodium-Glucose Cotransporter 2 Inhibitor Canagliflozin Antagonizes Salt-Sensitive Hypertension Through Modifying Transient Receptor Potential Channels 3 Mediated Vascular Calcium Handling

Background Salt-sensitive hypertension is highly prevalent and associated with cardiorenal damage. Large clinical trials have demonstrated that SGLT2 (sodium-glucose cotransporter 2) inhibitors exert hypotensive effect and cardiorenal protective benefits in patients with hypertension with and without diabetes. However, the underlying mechanism remains elusive. Methods and Results Dahl salt-sensitive rats and salt-insensitive controls were fed with 8% high-salt diet and some of them were treated with canagliflozin. The blood pressure, urinary sodium excretion, and vascular function were detected. Transient receptor potential channel 3 (TRPC3) knockout mice were used to explain the mechanism. Canagliflozin treatment significantly reduced high-salt-induced hypertension and this effect was not totally dependent on urinary sodium excretion in salt-sensitive hypertensive rats. Assay of vascular function and proteomics showed that canagliflozin significantly inhibited vascular cytoplasmic calcium increase and vasoconstriction in response to high-salt diet. High salt intake increased vascular expression of TRPC3 in salt-sensitive rats, which could be alleviated by canagliflozin treatment. Overexpression of TRPC3 mimicked salt-induced vascular cytosolic calcium increase in vitro and knockout of TRPC3 erased the antihypertensive effect of canagliflozin. Mechanistically, high-salt-induced activation of NCX1 (sodium-calcium exchanger 1) reverse mode increased cytoplasmic calcium level and vasoconstriction, which required TRPC3, and this process could be blocked by canagliflozin. Conclusions We define a previously unrecognized role of TRPC3/NCX1 mediated vascular calcium dysfunction in the development of high-salt-induced hypertension, which can be improved by canagliflozin treatment. This pathway is potentially a novel therapeutic target to antagonize salt-sensitive hypertension.

Identification of osteoporosis based on gene biomarkers using support vector machine

Osteoporosis is a major health concern worldwide. The present study aimed to identify effective biomarkers for osteoporosis detection. In osteoporosis, 559 differentially expressed genes (DEGs) were enriched in PI3K-Akt signaling pathway and Foxo signaling pathway. Weighted gene co-expression network analysis showed that green, pink, and tan modules were clinically significant modules, and that six genes (VEGFA, DDX5, SOD2, HNRNPD, EIF5B, and HSP90B1) were identified as “real” hub genes in the protein–protein interaction network, co-expression network, and 559 DEGs. The sensitivity and specificity of the support vector machine (SVM) for identifying patients with osteoporosis was 100%, with an area under curve of 1 in both training and validation datasets. Our results indicated that the current system using the SVM method could identify patients with osteoporosis.

The pro-inflammatory effect of triglyceride on human CD4+ T cells and experimental autoimmune uveitis

Aberrant lipid metabolism plays a role in inflammation and progression of autoimmune diseases but the definite mechanism remains unclear. In this study we investigate lipidomic profiles in Behçet's disease (BD) and the role of triglyceride (TAG) in the pathogenesis of autoimmune uveitis. Lipidomics revealed a distinct lipid metabolite profile including increased TAG metabolites in plasma of active BD patients. TAG could stimulate the proliferation, IL-17 and IFN-γ expression by CD4⁺ T cells and Th1, Th17 cell differentiation in vitro, but did not influence neutrophils. A922500 inhibited the TAG generation, ameliorated the EAU severity, decreased Th17 frequency and IL-17 expression by CD4⁺ T cells in vivo. The proteomocis analysis showed an up-regulation of apoptosis-related protein, Pik3r2, in CD4⁺ T cells from A922500-treated mice. In conclusion, TAG can stimulate human CD4⁺ T cells and the inhibition of its generation could significantly ameliorate EAU activity in association with down-regulated Th17 cell response.

TMT-Based Proteomic Explores the Influence of DHEA on the Osteogenic Differentiation of hBMSCs

Dehydroepiandrosterone (DHEA) has been revealed to implicate in facilitating osteoblast differentiation of human bone marrow mesenchymal stem cells (hBMSCs) and inhibiting osteoporosis (OP). However, the underlying molecular mechanism remains largely unknown. Here, we induced osteogenic differentiation of hBMSCs derived from elders using an osteogenic induction medium with or without DHEA. The results showed that osteogenic induction medium (OIM) with DHEA could significantly promote the proliferation and osteogenic differentiation of hBMSCs than OIM alone. By using a Tandem Mass Tag (TMT) labeling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology, we screened out 604 differentially expressed proteins (DEPs) with at least one unique peptide were identified [524: OIM vs. complete medium (CM), and 547: OIM+DHEA vs. CM], among these proteins, 467 DEPs were shared in these two different comparative groups. Bioinformatic analysis revealed these DEPs are mainly enriched in metabolic pathways. Interestingly, the expression levels of the DEPs in the metabolic pathways showed a more noticeable change in the OIM+DHEA vs. CM group than OIM vs. CM group. Moreover, the protein-protein interaction (PPI) network analysis revealed that three potential proteins, ATP5B, MT-CYB, and MT-ATP6, involved in energy metabolism, might play a key role in osteogenic differentiation induced by OIM+DHEA. These findings offer a valuable clue for us to better understand the underlying mechanisms involved in osteoblast differentiation of hBMSCs caused by DHEA and assist in applying DHEA in hBMSCs-based therapy for osteogenic regeneration.

Silencing Proteasome 26S Subunit ATPase 2 (PSMC2) Protects the Osteogenic Differentiation In Vitro and Osteogenesis In Vivo

Osteoporosis is a commonly seen degenerative bone disorder in the elderly and postmenopausal women, with a low bone mineral density as a major risk factor. The osteogenic potential of bone marrow stromal cells (BMSCs) showed to be impaired during osteoporosis. We established a postmenopausal osteoporosis model in ovariectomized (OVX) mice and found the upregulation of proteasome 26S subunit ATPase 2 (PSMC2) in OVX mice. PSMC2 silencing improved OVX-impaired biomechanical properties of mice femur, OVX-decreased BMD, and OVX-destroyed bone structure. Histopathological analysis indicated that PSMC2 silencing improved bone trabecular structure and increased the contents of collagen fibers and newly formed bone or cartilage in OVX mice. In the meantime, PSMC2 silencing increased Runx2, PI3K, Wnt3a, and β-catenin protein contents while reduced CTSK protein. Within BMSCs isolated from OVX mice, PSMC2 silencing promoted BMSC osteogenic differentiation and elevated osteogenic markers' protein contents, including HOXA10, Runx2, OCN, OPN, and COL1A2. In conclusion, PSMC2 expression is upregulated in the postmenopausal osteoporosis model in OVX mice. PSMC2 silencing promotes the osteogenic differentiation of BMSCs in vitro, promotes bone formation, and inhibits bone resorption in vivo.

Is hyperglycemia the only risk factor for implant in type 2 diabetics during the healing period?

OBJECTIVE

To determine whether risk factors other than hyperglycemia lead to failed osseointegration in patients with type 2 diabetes mellitus (T2DM) during the healing period.

MATERIALS AND METHODS

We compared the success rates between patients with and without T2DM during the healing period at our center. Bone marrow mesenchymal stem cells (BMSCs) were cultured from subjects. Proteomics was used to detect differentially expressed proteins (DEPs) among the DM failure (DM-F), DM success (DM-S), and control (Con) groups. The correlation between the expression levels of nine target DEPs and medium glucose concentrations was investigated.

RESULTS

Higher failure rates were observed in the T2DM patients. Fifty-two DEPs were found between the DM-F and DM-S groups. Seventy-three DEPs were found between the DM-F and Con groups. Forty-three DEPs were found between the DM-S and Con groups. Five target DEPs were expressed at the same levels in the medium with different glucose concentrations. Gene ontology annotation and functional enrichment analysis suggest that the DEPs detected in the DM-F group may affect the biological function and regulatory potential of BMSCs.

CONCLUSIONS

The DEPs detected in the DM-F group can be intervention targets for to prevent implant failure in T2DM patients. Risk factors besides hyperglycemia may affect osseointegration during healing period.

Linoleic acid inhibits in vitro function of human and murine dendritic cells, CD4+T cells and retinal pigment epithelial cells

PURPOSE

Increased linoleic acid (LA) was observed in acute anterior uveitis (AAU) patient feces in our previous study. To investigate the immunoregulatory effect of LA, we studied the effect of LA on human and murine dendritic cells (DCs), CD4⁺T cells, and retinal pigment epithelial (RPE) cells in vitro.

METHODS

The level of LA in feces from AAU patients and healthy individuals was measured by gas chromatography coupled with a mass spectrometer (GC-MS). The immunoregulatory effect of LA on human and murine DCs, CD4⁺ T cells, and RPE cells was evaluated by enzyme linked immunosorbent assay (ELISA) and flow cytometry (FCM). The effect of LA on DCs was evaluated by Tandem mass tag (TMT)-based proteomics analysis.

RESULTS

Increased LA was observed in feces from AAU patients (1018.35 ± 900.01 mg/kg) as compared with healthy individuals (472.55 ± 365.49 mg/kg, p = 0.0136). LA attenuated the antigen-presenting function of human and murine DCs by decreasing the expression of CD40, the secretion of IL-6 and IL-12p70, and the ability to shift naïve T cells towards T helper type 1 (Th1) and Th17 cells. LA also inhibited the secretion of MCP-1 and IL-8 from RPE cells. Proteomics analysis showed differential expression of 28 proteins, including squalene epoxidase (SQLE), farnesyl-diphosphate farnesyltransferase 1 (FDFT1), and cytochrome P450 family 51 subfamily A member 1 (CYP51A1), in LA-treated DCs compared with controls. LA also accelerated the apoptosis of DCs from healthy individuals.

CONCLUSION

LA inhibited the function of human and murine DCs, CD4⁺T cells, and RPE cells, regulated the expression of proteins, and promoted the apoptosis of human DCs. These results collectively suggest that LA might decrease the function of immune cells in vitro, and further studies are needed to investigate its role in the pathogenesis of AAU.

TMT proteomics analysis of intestinal tissue from patients of irritable bowel syndrome with diarrhea: Implications for multiple nutrient ingestion abnormality

Diarrheal irritable bowel syndrome (IBS-D) is a chronic functional bowel disease with no clear diagnostic markers and no satisfactory treatment strategies. In recent years, the importance of intestinal microstructure and function in IBS-D has been emphasized. However, the intestinal tissue proteomics of IBS-D patients has not been analyzed. Here, we systematically analyzed the molecule profiling of the intestinal tissues in IBS-D patients through tandem mass tag (TMT)-based proteomics for the first time, aiming to reveal the pathogenesis and provide evidence for diagnosis and treatment of IBS-D. Five IBS-D patients and five healthy subjects were selected, biopsy tissue samples from the junction of sigmoid and rectum were analyzed by TMT proteomics. Differentially expressed proteins were obtained and bioinformatics analysis was performed. Furthermore, parallel reaction monitoring (PRM) and q-PCR detection were applied to validate the differentially expressed proteins. Eighty differentially expressed proteins were screened, 48 of which were up-regulated and 32 were down-regulated (fold change >1.2, P < 0.05). Bioinformatics analysis showed that these proteins were significantly enriched in the nutrient ingestion pathways which are related to immune molecules. SELENBP1, VSIG2, HMGB1, DHCR7, BCAP31 and other molecules were significantly changed. Our study revealed the underlying mechanisms of IBS-D intestinal dysfunction. SIGNIFICANCE: Irritable bowel syndrome with diarrhea (IBS-D) is a worldwide chronic intestinal disease with no definite diagnostic markers. It is still a challenge to accurately locate the pathogenesis of patients for appropriate treatment strategy. Established proteomics studies of IBS-D are only based on urine, blood, or tissue samples from animals. Our study was the first TMT proteomics analysis on intestinal biopsy tissues of patients with IBS-D, which revealed the changes of molecular spectrum of actual intestinal conditions in patients with IBS-D. Some important molecules and signaling pathways have been found abnormal in our study, which were related with nutrient uptake. They not only provided preliminary clues for low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) intolerance, an unsolved conundrum of IBS-D, but also revealed obscure problems of protein, lipid, and other nutrients ingestion in IBS-D patients. Some of these differentially expressed molecules have been preliminarily verified, and will may be potential candidate molecules for diagnostic markers of IBS-D.

Analysis of the role of palmitoleic acid in acute anterior uveitis

PURPOSE

To study the role of palmitoleic acid (PA) in the pathogenesis of acute anterior uveitis (AAU).

METHODS

PA levels in feces from AAU patients were measured by gas chromatography coupled with a mass spectrometer (GC-MS) and compared with samples obtained from healthy individuals. Enzyme linked immunosorbent assay (ELISA) and flow cytometry (FCM) were used to assess the effect of PA on dendritic cells (DCs) and CD4⁺T cells obtained from mice, AAU patients and healthy individuals. C57BL/6 mice were fed with PA or vehicle and experimental autoimmune uveitis (EAU) was induced with a human retinal IRBP651-670 peptide. Disease severity of EAU was evaluated by clinical manifestation and histology. Differentiation of splenic Type 1 helper T cells (Th1) and Th17 cells was evaluated by FCM. Tandem mass tag (TMT)-based proteomics analysis was used to identify differentially expressed proteins following incubation of DCs with PA.

RESULTS

The fecal concentration of PA was increased in AAU patients as compared with healthy individuals. In vitro, PA promoted apoptosis of DCs and inhibited the secretion of TNF-α from mouse bone-marrow-derived dendritic cells (BMDCs) as well as in DCs from AAU patients and healthy individuals. It only decreased DCs surface marker expression and IL-12p70 secretion in BMDCs and healthy individuals DCs but not in AAU patient DCs. PA-treated BMDCs inhibited Th cell differentiation from mouse naïve CD4⁺T cells and IL-17 and IFN-γ secretion in co-culture supernatants. PA also inhibited the differentiation of Th cells and secretion of IFN-γ and IL-17 in CD4⁺T cells from mice, AAU patients and healthy individuals. In vivo, PA-treated EAU mice showed milder clinical and histopathological intraocular manifestations as compared with the control group. PA feeding inhibited differentiation of splenic Th17 cells, whereas Th1 cells were not affected. Up to 30 upregulated and 77 downregulated proteins were identified when comparing PA-treated DCs with controls.

CONCLUSION

An increased expression of fecal PA was observed in AAU patients. PA was shown to have immunoregulatory effects on DCs and CD4⁺T cells and attenuated disease severity in EAU mice.

Proteomic and Transcriptomic Approaches for Studying Bone Regeneration in Health and Systemically Compromised Conditions

Bone regeneration is a complex biological process, where the molecular mechanisms are only partially understood. In an ageing population, where the prevalence of chronic diseases with an impact on bone metabolism is increasing, it becomes crucial to identify new strategies that would improve regenerative outcomes also in medically compromised patients. In this context, omics are demonstrating a great potential, as they offer new insights on the molecular mechanisms regulating physiologic/pathologic bone healing and, at the same time, allow the identification of new diagnostic and therapeutic targets. This review provides an overview on the current evidence on the use of transcriptomic and proteomic approaches in bone regeneration research, particularly in relation to type 1 diabetes and osteoporosis, and discusses future scenarios and potential benefits and limitations on the integration of multi-omics. It is suggested that future research will leverage the synergy of omics with statistical modeling and bioinformatics to prompt the understanding of the biology underpinning bone formation in health and medically compromised conditions. With an eye toward personalized medicine, new strategies combining the mining of large datasets and bioinformatic data with a detailed characterization of relevant phenotypes will need to be pursued to further the understanding of disease mechanisms.