Locally Secreted Semaphorin 4D Is Engaged in Both Pathogenic Bone Resorption and Retarded Bone Regeneration in a Ligature-Induced Mouse Model of Periodontitis.

It is well known that Semaphorin 4D (Sema4D) inhibits IGF-1-mediated osteogenesis by binding with PlexinB1 expressed on osteoblasts. However, its elevated level in the gingival crevice fluid of periodontitis patients and the broader scope of its activities in the context of potential upregulation of osteoclast-mediated periodontal bone-resorption suggest the need for further investigation of this multifaceted molecule. In short, the pathophysiological role of Sema4D in periodontitis requires further study. Accordingly, attachment of the ligature to the maxillary molar of mice for 7 days induced alveolar bone-resorption accompanied by locally elevated, soluble Sema4D (sSema4D), TNF-α and RANKL. Removal of the ligature induced spontaneous bone regeneration during the following 14 days, which was significantly promoted by anti-Sema4D-mAb administration. Anti-Sema4D-mAb was also suppressed in vitro osteoclastogenesis and pit formation by RANKL-stimulated BMMCs. While anti-Sema4D-mAb downmodulated the bone-resorption induced in mouse periodontitis, it neither affected local production of TNF-α and RANKL nor systemic skeletal bone remodeling. RANKL-induced osteoclastogenesis and resorptive activity were also suppressed by blocking of CD72, but not Plexin B2, suggesting that sSema4D released by osteoclasts promotes osteoclastogenesis via ligation to CD72 receptor. Overall, our data indicated that ssSema4D released by osteoclasts may play a dual function by decreasing bone formation, while upregulating bone-resorption.

Dual-Function Semaphorin 4D Released by Platelets: Suppression of Osteoblastogenesis and Promotion of Osteoclastogenesis.

Effects of the antiosteoblastogenesis factor Semaphorin 4D (Sema4D), expressed by thrombin-activated platelets (TPs), on osteoblastogenesis, as well as osteoclastogenesis, were investigated in vitro. Intact platelets released both Sema4D and IGF-1. However, in response to stimulation with thrombin, platelets upregulated the release of Sema4D, but not IGF-1. Anti-Sema4D-neutralizing monoclonal antibody (mAb) upregulated TP-mediated osteoblastogenesis in MC3T3-E1 osteoblast precursors. MC3T3-E1 cells exposed to TPs induced phosphorylation of Akt and ERK further upregulated by the addition of anti-sema4D-mAb, suggesting the suppressive effects of TP-expressing Sema4D on osteoblastogenesis. On the other hand, TPs promoted RANKL-mediated osteoclastogenesis in the primary culture of bone-marrow-derived mononuclear cells (BMMCs). Among the known three receptors of Sema4D, including Plexin B1, Plexin B2 and CD72, little Plexin B2 was detected, and no Plexin B1 was detected, but a high level of CD72 mRNA was detected in RANKL-stimulated BMMCs by qPCR. Both anti-Sema4D-mAb and anti-CD72-mAb suppressed RANKL-induced osteoclast formation and bone resorptive activity, suggesting that Sema4D released by TPs promotes osteoclastogenesis via ligation to a CD72 receptor. This study demonstrated that Sema4D released by TPs suppresses osteogenic activity and promotes osteoclastogenesis, suggesting the novel property of platelets in bone-remodeling processes.

Nitroalkene fatty acids modulate bile acid metabolism and lung function in obese asthma.

Bile acid profiles are altered in obese individuals with asthma. Thus, we sought to better understand how obesity-related systemic changes contribute to lung pathophysiology. We also test the therapeutic potential of nitro-oleic acid (NO2-OA), a regulator of metabolic and inflammatory signaling pathways, to mitigate allergen and obesity-induced lung function decline in a murine model of asthma. Bile acids were measured in the plasma of healthy subjects and individuals with asthma and serum and lung tissue of mice with and without allergic airway disease (AAD). Lung function, indices of inflammation and hepatic bile acid enzyme expression were measured in obese mice with house dust mite-induced AAD treated with vehicle or NO2-OA. Serum levels of glycocholic acid and glycoursodeoxycholic acid clinically correlate with body mass index and airway hyperreactivity whereas murine levels of ß-muricholic acid and tauro-ß-muricholic acid were significantly increased and positively correlated with impaired lung function in obese mice with AAD. NO2-OA reduced murine bile acid levels by modulating hepatic expression of bile acid synthesis enzymes, with a concomitant reduction in small airway resistance and tissue elastance. Bile acids correlate to body mass index and lung function decline and the signaling actions of nitroalkenes can limit AAD by modulating bile acid metabolism, revealing a potential pharmacologic approach to improving the current standard of care.

Effect of the filler grade on the characteristics and the sublingual permeability of atropine sulfate fast disintegrating sublingual tablets.

Context: AS FDSTs will provide an accessible alternative for AS autoinjector (ATROPEN®), and a noninvasive first-aid antidote for the treatment of organophosphate (OP) poisoning and reduce the number of fatalities due to nerve gas attacks or OP pesticide poisoning. Objective: The effects of changing the filler grade on the characteristics of atropine sulfate (AS) fast disintegrating sublingual tablets (FDSTs) and AS sublingual permeability were investigated in order to optimize the formulation of AS FDSTs and, therefore, AS sublingual permeability. Methods: Two batches of AS FDSTs containing AS 8 mg were formulated and manufactured using two different filler grades: microcrystalline cellulose (MCC) UF-702 (formulation A) and MCC PH-301 (formulation B). Several United States Pharmacopeia (USP) and non-USP physical tests were performed to evaluate the AS FDSTs' characteristics. The AS permeability from the two AS FDST batches were evaluated using Franz cells through excised porcine sublingual membranes. Results were statistically compared at p < .05. Results: Both batches passed the content uniformity and friability tests. Formulation A tablets were significantly different from formulation A tablets and resulted in better powder flowability, higher breaking force, faster disintegration, faster dissolution rate, higher water uptake, and higher AS permeability. Conclusion: The selection of the filler grade to be used in the formulation of AS FDSTs can significantly impact their characteristics and significantly affect AS sublingual permeability, which can be used to improve the sublingual delivery of AS and the potential of using AS FDSTs as an alternative dosage form for the first-aid treatment of OP poisoning.

Effect of Fast-Disintegrating Tablets' Characteristics on the Sublingual Permeability of Atropine Sulfate for the Potential Treatment of Organophosphates Toxicity.

Atropine sulfate (AS) fast-disintegrating sublingual tablets (FDSTs) were tested for AS sublingual permeation's feasibility as a potential alternative dosage form to treat organophosphates (OP) toxicity. More than 12,000 OP pesticide toxicity cases were reported in the USA from 2011 to 2014. AS is the recommended antidote for OP toxicity; however, it is only available as an ATROPEN® auto-injector, an IM injection, for self-administration, which is associated with several drawbacks and limitations. Six AS FDST batches were formulated and characterized. Two tablet sizes, group A weighing 150 mg and group B weighing 50 mg, were formulated with three different AS doses: 2 mg (A1 and B1), 4 mg (A2 and B2), and 8 mg (A3 and B3). AS in vitro diffusion and sublingual permeation were investigated in Franz cells using a cellulose membrane and an excised porcine sublingual membrane. The effect of AS load and tablet size on sublingual permeation was also evaluated. All batches passed quality control tests. AS FDSTs' size and AS load had a significant effect on tablet disintegration time and drug dissolution, which significantly impacted AS concentration gradient across the diffusional membrane. Group B FDSTs (smaller tablets) resulted in a significantly higher initial permeation (JAUC0-15) compared to group A FDSTs. Also, the cumulative AS (JAUC0-90) and AS influx (J) increased linearly with increasing AS dose. These AS FDSTs have the potential to be explored in vivo to determine the required bioequivalent sublingual AS dose as an alternative dosage form for the treatment of OP toxicity.