Loss of endothelial sulfatase-1 after experimental sepsis attenuates subsequent pulmonary inflammatory responses.
Kaori OshimaXiaorui HanYilan OuyangRana El MasriYimu YangSarah M HaegerSarah A McMurtryTrevor C LanePavel Davizon-CastilloFuming ZhangXinping YueRomain R VivèsRobert J LinhardtEric P SchmidtPublished in: American journal of physiology. Lung cellular and molecular physiology (2019)
Sepsis patients are at increased risk for hospital-acquired pulmonary infections, potentially due to postseptic immunosuppression known as the compensatory anti-inflammatory response syndrome (CARS). CARS has been attributed to leukocyte dysfunction, with an unclear role for endothelial cells. The pulmonary circulation is lined by an endothelial glycocalyx, a heparan sulfate-rich layer essential to pulmonary homeostasis. Heparan sulfate degradation occurs early in sepsis, leading to lung injury. Endothelial synthesis of new heparan sulfates subsequently allows for glycocalyx reconstitution and endothelial recovery. We hypothesized that remodeling of the reconstituted endothelial glycocalyx, mediated by alterations in the endothelial machinery responsible for heparan sulfate synthesis, contributes to CARS. Seventy-two hours after experimental sepsis, coincident with glycocalyx reconstitution, mice demonstrated impaired neutrophil and protein influx in response to intratracheal lipopolysaccharide (LPS). The postseptic reconstituted glycocalyx was structurally remodeled, with enrichment of heparan sulfate disaccharides sulfated at the 6-O position of glucosamine. Increased 6-O-sulfation coincided with loss of endothelial sulfatase-1 (Sulf-1), an enzyme that specifically removes 6-O-sulfates from heparan sulfate. Intravenous administration of Sulf-1 to postseptic mice restored the pulmonary response to LPS, suggesting that loss of Sulf-1 was necessary for postseptic suppression of pulmonary inflammation. Endothelial-specific knockout mice demonstrated that loss of Sulf-1 was not sufficient to induce immunosuppression in non-septic mice. Knockdown of Sulf-1 in human pulmonary microvascular endothelial cells resulted in downregulation of the adhesion molecule ICAM-1. Taken together, our study indicates that loss of endothelial Sulf-1 is necessary for postseptic suppression of pulmonary inflammation, representing a novel endothelial contributor to CARS.
Keyphrases
- endothelial cells
- pulmonary hypertension
- inflammatory response
- high glucose
- acute kidney injury
- oxidative stress
- intensive care unit
- healthcare
- type diabetes
- end stage renal disease
- septic shock
- chronic kidney disease
- emergency department
- immune response
- escherichia coli
- staphylococcus aureus
- high dose
- metabolic syndrome
- cell proliferation
- ejection fraction
- skeletal muscle
- cystic fibrosis
- small molecule
- prognostic factors
- toll like receptor
- wild type
- peritoneal dialysis
- protein protein