The effects of carbon monoxide releasing molecules on paraquat-induced pulmonary interstitial inflammation and fibrosis.

Paraquat, an herbicide used extensively worldwide, can cause severe toxicity in humans and animals, leading to irreversible, lethal lung fibrosis. The potential of CO-releasing molecules (CORMs), substances that release CO (Carbon monoxide) within animal tissues, for treating paraquat-induced ROS generation and inflammation is investigated here. Our results show that the fast CO releaser CORM-3 (4-20 µM) acts as a potential scavenger of free radicals and decreases fibrosis progression by inhibiting paraquat-induced overexpression of connective tissue growth factor and angiotensin II in MRC-5 cells. The slow CO releaser CORM-A1 (5 mg/kg) clearly decreased expression of the lung profibrogenic cytokines COX-2, TNF-α, and α-SMA and serum hydroxyproline, resulting in a lower mortality rate in paraquat-treated mice. Mice treated with higher-dose CORM-A1 (10 mg/kg) had relatively intact lung lobes and fewer fibrotic patches by gross observation, with less collagen deposition, mesangial matrix accumulation, and pulmonary fibrosis resulting from the mitigation of TGF-ß overexpression. In conclusion, our data demonstrate for the first time that CORM-A1 alleviated the development of the fibrotic process and improved survival rate in mice exposed to PQ, would be an attractive therapeutic approach to attenuate the progression of pulmonary fibrosis following PQ exposure.

Sclerostin vaccination mitigates estrogen deficiency induction of bone mass loss and microstructure deterioration.

Sclerostin (SOST) is a Wnt signaling inhibitor detrimental to osteogenic differentiation and bone mineral acquisition. While control of SOST action delays the pathogenesis of skeletal disorders, the effects of SOST vaccination on the estrogen deficiency-induced bone deterioration remain elusive. In this study, we generated a SOST-Fc fusion protein which was composed of a SOST peptide Pro-Asn-Ala-Ile-Gly along with an IgG Fc fragment. SOST-Fc vaccination increased serum anti-SOST antibody levels and reduced serum SOST concentrations in mice. In vitro, anti-SOST serum attenuated the SOST-induced inhibition of osteogenic gene expression in osteoblast cultures. Administration with SOST-Fc increased serum levels of bone formation marker osteocalcin and alleviated the ovariectomy escalation of serum resorption markers CTX-1 and TRAP5b concentrations. It remarkably lessened the estrogen deficiency-mediated deterioration of bone mineral density, morphometric characteristics of trabecular bone, and mechanical strength of femurs and lumbar spines. The SOST-Fc-treated skeletal tissue exhibited moderate responses to the adverse actions of ovariectomy to bone mineral accretion, osteoclast surface, trabecular separation, and fatty marrow histopathology. SOST-Fc treatment increased serum osteoclast-inhibitory factor osteoprotegrin levels in conjunction with strong Wnt3a, ß-catenin, and TCF4 immunostaining in osteoblasts, whereas it weakened the estrogen deficiency enhancement of osteoclast-promoting factor receptor activator of nuclear factor-κB ligand. Taken together, blockade of SOST action by SOST-Fc vaccination sustains Wnt signaling, which harmonizes bone mineral accretion and resorption reactions and thereby ameliorates ovariectomy-induced bone loss. This study highlights SOST-Fc fusion protein as a new molecular therapeutic potential for preventing from osteoporotic disorders.