The antiprotease SPINK7 serves as an inhibitory checkpoint for esophageal epithelial inflammatory responses

Loss of barrier integrity has an important role in eliciting type 2 immune responses, yet the molecular events that initiate and connect this with allergic inflammation remain unclear. We reveal an endogenous, homeostatic mechanism that controls barrier function and inflammatory responses in esophageal allergic inflammation. We show that a serine protease inhibitor, SPINK7 (serine peptidase inhibitor, kazal type 7), is part of the differentiation program of human esophageal epithelium and that SPINK7 depletion occurs in a human allergic, esophageal condition termed eosinophilic esophagitis. Experimental manipulation strategies reducing SPINK7 in an esophageal epithelial progenitor cell line and primary esophageal epithelial cells were sufficient to induce barrier dysfunction and transcriptional changes characterized by loss of cellular differentiation and altered gene expression known to stimulate allergic responses (for example, FLG and SPINK5). Epithelial silencing of SPINK7 promoted production of proinflammatory cytokines including thymic stromal lymphopoietin (TSLP). Loss of SPINK7 increased the activity of urokinase plasminogen-type activator (uPA), which in turn had the capacity to promote uPA receptor-dependent eosinophil activation. Treatment of epithelial cells with the broad-spectrum antiserine protease, α1 antitrypsin, reversed the pathologic features associated with SPINK7 silencing. The relevance of this pathway in vivo was supported by finding genetic epistasis between variants in TSLP and the uPA-encoding gene, PLAU We propose that the endogenous balance between SPINK7 and its target proteases is a key checkpoint in regulating mucosal differentiation, barrier function, and inflammatory responses and that protein replacement with antiproteases may be therapeutic for select allergic diseases.

The effect of harvesting the central one-third of the patellar tendon on patellofemoral contact pressure

This study assessed whether removing the central one-third of the patellar tendon, with or without side-to-side repair of the patellar tendon defect, would alter patellofemoral pressure. Patellofemoral pressure was assessed by testing five stable knees from five different cadaveric donors on a specially designed hydraulic knee machine. Patellofemoral joint pressures were measured by placing pressure-sensitive film into the patellofemoral articulation. The joint was loaded in a static fashion, with quadriceps forces consistent with walking (647 N) and stair climbing (1923 N), at 30 degrees, 60 degrees, and 90 degrees of knee flexion. Using the same knees, the central one-third of the patellar tendon was then sectioned, and patellofemoral joint pressure measurements were repeated at identical knee flexion angles and quadriceps-forces. Side-to-side repair of the patellar tendon defect was performed and patellofemoral joint pressure measurements were repeated. There were no statistically significant differences between the control and sectioned values or between the control and repaired defect values. These results suggest that harvesting the central one-third of the patellar tendon--with or without side-to-side repair of the patellar tendon defect--does not alter patellofemoral pressures.