Knockout of hyaluronan synthase 1, but not 3, impairs formation of the retrocalcaneal bursa

Abstract

Hyaluronan (HA), a high molecular weight non-sulfated glycosaminoglycan, is an integral component of the extracellular matrix of developing and mature connective tissues including tendon. There are few published reports quantifying HA content during tendon growth and maturation, or detailing its effects on the mechanical properties of the tendon extracellular matrix. Therefore, the goal of the current study was to examine the role of HA synthesis during post-natal skeletal growth and maturation, and its influence on tendon structure and biomechanical function. For this purpose, the morphological, biochemical, and mechanical properties of Achilles tendons from wild type (WT) and hyaluronan synthase 1 and 3 deficient mouse strains (Has1 (Has1KO), Has3 (Has3KO), and Has1 3 (Has1/3KO)) were determined at 4, 8, and 12 weeks of age. Overall, HAS-deficient mice did not show any marked differences from WT mice in Achilles tendon morphology or in the HA and chondroitin/dermatan sulfate (CS/DS) contents. However, HAS1-deficiency (in the single or Has1/3 double KO) impeded post-natal formation of the retrocalcaneal bursa, implicating HAS1 in regulating HA metabolism by cells lining the bursal cavity. Together, these data suggest that HA metabolism via HAS1 and HAS3 does not markedly influence the extracellular matrix structure or function of the tendon body, but plays a role in the formation/maintenance of peritendinous bursa. Additional studies are warranted to elucidate the relationship of HA and CS/DS metabolism to tendon healing and repair in vivo. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2622-2632, 2018.

Hyaluronic acid synthesis, degradation, and crosslinking in equine osteoarthritis: TNF-α-TSG-6-mediated HC-HA formation

“…HA production in mammals is controlled by three isoforms of the enzyme hyaluronan synthase, HAS1 , HAS2 , and HAS3 [ 42 ]. HAS2 is critical to development and is found in greatest abundance in adult tissues [ 43 ], but any specific functions of each HAS isoform in various tissues are poorly understood [ 43 ].…”

Hyaluronan biology: A complex balancing act of structure, function, location and context

“…On the other hand, Has1 and Has3 knockout mice are phenotypically less dramatic. Has1 deficiency is associated with a failure to form the retrocalcaneal bursa [42], whereas Has3 loss results in a migratory defect in vascular smooth muscle cells that results in decreased neointimal formation following endothelial injury [43], as well as abnormal neuronal activity and seizures [44]. Interestingly, the combined deficiency of Has1 and Has3 deficiency is associated with increased inflammation and accelerated wound closure of full thickness wounds [45].…”

In‐Vivo Efficacy of Recombinant Human Hyaluronidase (rHuPH20) Injection for Accelerated Healing of Murine Retrocalcaneal Bursitis and Tendinopathy

“…HA and chondroitin sulfate/dermatan sulfate (CS/DS) contents of the Achilles tendon and surrounding peritenon were quantified as previously described . Tissue pools (Supplementary Table S1) were digested with 150 µl of Proteinase K (10 mg/ml in PBS) at 55°C for 18 h prior to isolation of glycosaminoglycans (GAGs), chondroitinase ABC digestions, fluorotaging, and electrophoretic separation of ΔdiHA, Δdi0S, Δdi6S, and Δdi4S .…”

“…Total HA and CS/DS content was calculated on a per tendon basis. FACE analyses were initially conducted on n = 6 or n = 8 tendons per pool, to ascertain that the amounts of HA and CS/DS in the digested tissue pools was within the sensitivity range of the FACE assay . Additional pools were then reduced to n = 4 tendons to minimize the number of mice used.…”