Interleukin-8 production from human umbilical vein endothelial cells during brief hyperglycemia: the effect of tumor necrotic factor-alpha

Integrated proteomic analysis of tumor necrosis factor α and interleukin 1β-induced endothelial inflammation

The vascular endothelium provides a unique interaction plane for plasma proteins and leukocytes in inflammation. The pro-inflammatory cytokines Tumor Necrosis Factor α (TNFα) and interleukin 1β (IL-1β) have a profound effect on endothelial cells, which includes increased levels of adhesion molecules and a disrupted barrier function. To assess the endothelial response to these cytokines at the protein level, we evaluated changes in the whole proteome, cell surface proteome and phosphoproteome after 24 h of cytokine treatment. The effects of TNFα and IL-1β on endothelial cells were strikingly similar and included changes in proteins not previously associated with endothelial inflammation. Temporal profiling revealed time-dependent proteomic changes, including a limited number of early responsive proteins such as adhesion receptors ICAM1 and SELE. In addition, this approach uncovered a greater number of late responsive proteins, including proteins related to self-antigen peptide presentation, and a transient increase in ferritin. Peptide-based cell surface proteomics revealed extensive changes at the cell surface, which were in agreement with the whole proteome. In addition, site-specific changes within ITGA5 and ICAM1 were detected. Combined, our integrated proteomic data provide detailed information on endothelial inflammation, emphasize the role of the extracellular matrix therein, and include potential targets for therapeutic intervention. SIGNIFICANCE: Pro-inflammatory cytokines induce the expression of cell adhesion molecules in vascular endothelial cells. These molecules mediate the adhesion and migration of immune cells across the vessel wall, which is a key process to resolve infections in the underlying tissue. Dysregulation of endothelial inflammation can contribute to vascular diseases and the vascular endothelium is therefore an attractive target to control inflammation. Current strategies targeting endothelial adhesion molecules, including PECAM, CD99, ICAM1 and VCAM1 do not completely prevent transmigration. To identify additional therapeutic targets, we mapped the endothelial proteome after pro-inflammatory cytokine treatment. In addition to the whole proteome, we assessed the surface proteome to focus on cell adhesion molecules, and the phosphoproteome to uncover protein activation states. Here, we present an integrated overview of affected processes which further improves our understanding of endothelial inflammation and may eventually aid in therapeutic intervention of imbalanced inflammation.

Glucagon-like peptide-1 and vitamin D: anti-inflammatory response in diabetic kidney disease in db/db mice and in cultured endothelial cells

BACKGROUND

Glucagon-like peptide-1 (GLP-1) is a gut incretin hormone that stimulates insulin secretion and may affect the inflammatory pathways involved in diabetes mellitus. Calcitriol, an active form of vitamin D, plays an important role in renal, endothelial and cardiovascular protection. We evaluated the anti-inflammatory and histologic effects of a GLP-1 analogue (liraglutide) and of calcitriol in a db/db mouse diabetes model and in endothelial cells exposed to a diabetes-like environment.

METHODS

Diabetic db/db mice were treated with liraglutide and calcitriol for 14 weeks, after which the kidneys were perfused and removed for mRNA and protein analysis and histology. Endothelial cells were stimulated with advanced glycation end products (AGEs), glucose, liraglutide and calcitriol. Total RNA and protein were extracted and analysed for the expression of selected inflammatory markers.

RESULTS

Typical histological changes, glomerular enlargement and mesangial expansion were seen in db/db mice compared with control mice. Glomerular hypertrophy was ameliorated with liraglutide, compared with db/db controls. Liraglutide up-regulated endothelial nitric oxide synthase protein expression compared with the db/db control group and down-regulated p65 protein expression. Calcitriol did not further improve the beneficial effect observed on protein expression. In endothelial cells, liraglutide treatment exhibited a dose-dependent ability to prevent an inflammatory response in the selected markers: thioredoxin-interacting protein, p65, IL6 and IL8. In most gene and protein expressions, addition of calcitriol did not enhance the effect of liraglutide.

CONCLUSIONS

The GLP-1 analogue liraglutide prevented the inflammatory response observed in endothelial cells exposed to a diabetes-like environment and in db/db mice at the level of protein expression and significantly ameliorated the glomerular hypertrophy seen in the diabetic control group. Copyright © 2016 John Wiley & Sons, Ltd.

Traumatic brain injury: pathophysiology for neurocritical care

Severe cases of traumatic brain injury (TBI) require neurocritical care, the goal being to stabilize hemodynamics and systemic oxygenation to prevent secondary brain injury. It is reported that approximately 45 % of dysoxygenation episodes during critical care have both extracranial and intracranial causes, such as intracranial hypertension and brain edema. For this reason, neurocritical care is incomplete if it only focuses on prevention of increased intracranial pressure (ICP) or decreased cerebral perfusion pressure (CPP). Arterial hypotension is a major risk factor for secondary brain injury, but hypertension with a loss of autoregulation response or excess hyperventilation to reduce ICP can also result in a critical condition in the brain and is associated with a poor outcome after TBI. Moreover, brain injury itself stimulates systemic inflammation, leading to increased permeability of the blood–brain barrier, exacerbated by secondary brain injury and resulting in increased ICP. Indeed, systemic inflammatory response syndrome after TBI reflects the extent of tissue damage at onset and predicts further tissue disruption, producing a worsening clinical condition and ultimately a poor outcome.

Elevation of blood catecholamine levels after severe brain damage has been reported to contribute to the regulation of the cytokine network, but this phenomenon is a systemic protective response against systemic insults. Catecholamines are directly involved in the regulation of cytokines, and elevated levels appear to influence the immune system during stress. Medical complications are the leading cause of late morbidity and mortality in many types of brain damage. Neurocritical care after severe TBI has therefore been refined to focus not only on secondary brain injury but also on systemic organ damage after excitation of sympathetic nerves following a stress reaction.

Low-level laser irradiation effect on endothelial cells under conditions of hyperglycemia

Diabetes mellitus is considered to be a very serious lifestyle disease leading to cardiovascular complications and impaired wound healing observed in the diabetic foot syndrome. Chronic hyperglycemia is the source of the endothelial activation. The inflammatory process in diabetes is associated with the secretion of inflammatory cytokines by endothelial cells, e.g., tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6). The method of phototherapy using laser beam of low power (LLLT-low-level laser therapy) effectively supports the conventional treatment of diabetic vascular complications such as diabetic foot syndrome. The aim of our study was to evaluate the effect of low-power laser irradiation at two wavelengths (635 and 830 nm) on the secretion of inflammatory factors (TNF-α and IL-6) by the endothelial cell culture-HUVEC line (human umbilical vein endothelial cell)-under conditions of hyperglycemia. It is considered that adverse effects of hyperglycemia on vascular endothelial cells may be corrected by the action of LLLT, especially with the wavelength of 830 nm. It leads to the reduction of TNF-α concentration in the supernatant and enhancement of cell proliferation. Endothelial cells play an important role in the pathogenesis of diabetes; however, a small number of studies evaluate an impact of LLLT on these cells under conditions of hyperglycemia. Further work on this subject is warranted.