Luke, E. | bioRxiv Science

bioRxiv2022

Targeting Damaged Collagen for Intra-Articular Delivery of Therapeutics using Collagen Hybridizing Peptides

The objective of this study was to investigate the potential of collagen hybridizing peptides (CHPs), which bind to denatured collagen, to extend the retention time of near-infrared fluorophores (NIRF) following intra-articular (IA) injection in rat knee joints. CHPs were synthesized with a NIRF conjugated to N-terminus. Male Sprague-Dawley rats were assigned to one of four experimental groups: healthy, CHP; osteoarthritis (OA), CHP; healthy, scrambled-sequence CHP (sCHP), which has no collagen binding affinity; or OA, sCHP. Animals in the OA groups received an IA injection of monosodium iodoacetate to induce OA. All animals then received the corresponding CHP injection. Animals were imaged repeatedly over two weeks using an in vivo fluorescence imaging system. Joint components were isolated and imaged to determine CHP binding distribution. Safranin-O and Fast Green histological staining was performed to confirm the development of OA. CHPs were found to be retained within the joint following IA injection in both healthy and OA animals for the full study period. In contrast, sCHPs were cleared within 24-48 hours. CHP signal was significantly greater (p<0.05) in OA joints when compared to healthy joints. At the two-week end point, multiple joint components retained CHPs, including cartilage, meniscus, and synovium. CHPs extended the retention time of NIRFs following IA injection in healthy and OA knee joints by binding to multiple collagenous tissues in the joint. These results support the pursuit of further research on CHP based therapeutics for IA treatment of OA.

bioengineering↗

bioRxiv2020

Obesity control by SHIP inhibition requires pan-paralog inhibition and an intact eosinophil compartment

Previously a small molecule SHIP inhibitor, K118, was shown to reverse high-fat diet induced obesity and improve blood glucose regulation in obese mice. K118 treatment was also found to increase the frequency and number of IL-4 producing eosinophils in the visceral fat as well two potent immunoregulatory myeloid cell populations: M2-polarized macrophages and myeloid derived suppressor cells (MDSC) suggesting an immune regulatory mechanism. However, the cell(s) or SHIP paralog that should be targeted to improve metabolic regulation was not defined. Here we extend our understanding of how chemical inhibition of SHIP paralogs improves metabolic regulation during excess caloric intake. Here we compare SHIP inhibitors in an obesity prevention model and find that selective inhibitors for SHIP1 or SHIP2 lack the ability to prevent weight gain and body fat accumulation during increased caloric intake. Surprisingly, only pan-SHIP1/2 inhibitors can prevent diet-induced obesity. We confirm that both SHIP1 and SHIP2 must be targeted by showing that dual treatment with the SHIP1 and SHIP2 selective inhibitors can reduced adiposity caused by excess caloric consumption. We also show that pan-SHIP1/2 inhibitors of two different chemical classes can control diet-induced obesity and improve blood glucose regulation. Intriguingly, we find that both classes of pan-SHIP1/2 inhibitors require an intact eosinophil compartment to prevent diet-related fat accumulation demonstrating pan-SHIP1/2 inhibitors act via the VAT innate immune compartment to control adiposity However, improved blood glucose regulation by pan-SHIP1/2 inhibition is not dependent upon eosinophils, indicating a separate mechanism of action for diet-related loss of glucose regulation.

immunology↗