Loss of direct adrenergic innervation after peripheral nerve injury causes lymph node expansion through IFN-γ

Peripheral nerve injury can cause debilitating disease and immune cell-mediated destruction of the affected nerve. While the focus has been on the nerve-regenerative response, the effect of loss of innervation on lymph node function is unclear. Here, we show that the popliteal lymph node (popLN) receives direct neural input from the sciatic nerve and that sciatic denervation causes lymph node expansion. Loss of sympathetic, adrenergic tone induces the expression of IFN-γ in LN CD8 T cells, which is responsible for LN expansion. Surgery-induced IFN-γ expression and expansion can be rescued by β2 adrenergic receptor agonists but not sensory nerve agonists. These data demonstrate the mechanisms governing the pro-inflammatory effect of loss of direct adrenergic input on lymph node function.

One concept does not fit all: the immune system in different forms of acute kidney injury

Renal and immune systems maintain body homoeostasis during physiological fluctuations and following tissue injury. The immune system plays a central role during acute kidney injury (AKI), adapting evolutional systems programmed for host defence and minimizing unnecessary collateral damage. Indeed, depending upon the disease context, the impact of the immune system upon the manifestations and consequences of AKI can be quite different. Here we provide an overview of the known and unknown involvement of the immune system within the wide range of different forms of AKI, to oppose oversimplification and to endorse deeper insights into the pathogenesis of the different diseases causing kidney injury. This approach may help to overcome some of the current hurdles in translational AKI research and the development of specific treatments for the different diseases, all presenting with an acute increase in serum creatinine or decline in urinary output. One concept does not fit all.

Modeling how CD46 deficiency predisposes to atypical hemolytic uremic syndrome

Mutations in complement regulatory proteins predispose to the development of aHUS. Approximately 50% of patients bear a mutation in one of three complement control proteins, factor H, factor I, or membrane cofactor protein (MCP; CD46). Another membrane regulator that is closely related to MCP, decay accelerating factor (DAF; CD55) thus far has shown no association with aHUS and continues to be investigated. The goal of this study was to compare the regulatory profile of MCP and DAF and to assess how alterations in MCP predispose to complement dysregulation. We employed a model system of complement activation on Chinese hamster ovary (CHO) cell transfectants. The four regularly expressed isoforms of MCP and DAF inhibited C3b deposition by the alternative pathway. DAF, but not MCP, inhibited the classical pathway. Most patients with MCP-aHUS are heterozygous and express only 25-50% of the wild-type protein. We, therefore, analyzed the effect of reduced levels of wild-type MCP and found that cells with lowered expression levels were less efficient in inhibiting alternative pathway activation. Further, a dysfunctional MCP mutant, expressed at normal levels and identified in five patients with aHUS (S206P), failed to protect against C3b amplification on CHO cells, even if expression levels were increased 10-fold. Our results add new information relative to the necessity for appropriate expression levels of MCP and further implicate the alternative pathway in disease processes such as aHUS.

A complement receptor for opsonized immune complexes on erythrocytes from Oncorhynchus mykiss but not Ictalarus punctatus

Immune complexes activate the classical pathway of complement resulting in the covalent deposition of fragments of the third (C3b) and fourth (C4b) components of complement, thus opsonizing the complexes for uptake by CD35 found on human erythrocytes. The complexes are then transported to and cleared from the circulation by the reticuloendothelial system. It has been shown that rainbow trout can remove immune complexes from the circulation in a complement-dependent manner similar to that found in the human. However, the cell or cell types involved have not been identified. The purpose of this study was to investigate whether a complement-dependent immune adherence receptor is expressed on erythrocytes from the rainbow trout (Oncorhynchus mykiss) and the channel catfish (Ictalarus punctatus). Coating fluorescent microparticles with BSA, and then binding them to anti-BSA created an artificial immune complex that was incubated with normal fish serum, normal human serum or EDTA-treated serum. The complement-coated immune complexes were then incubated with either fish or human erythrocytes and analyzed for binding by flow cytometry and further visualized by fluorescence microscopy. Our results indicate that erythrocytes from rainbow trout are capable of binding immune complexes when pretreated with serum from either the trout or human, but not when pretreated with serum containing EDTA. By contrast, erythrocytes from the channel catfish did not bind immune complexes pretreated with autologous or human serum. These data suggest that differences exist in receptor distribution between two closely related species of fish, and a potentially homologous relationship in receptor expression, and possibility function, exist between two highly divergent species.

Synthesis and Biological Evaluation of 14-Alkoxymorphinans. 21. Novel 4-Alkoxy and 14-Phenylpropoxy Derivatives of the μ Opioid Receptor Antagonist Cyprodime

The synthesis, biological, and pharmacological evaluation of novel derivatives of cyprodime are described. Their binding affinities at mu, delta, and kappa opioid receptors were evaluated using receptor binding assay. It was observed that the affinity of these compounds was sensitive to the character and length of the substituent in position 4. Further prolongation of the 4-alkoxy group of cyprodime (1) and its 4-butoxy analogue 2 is detrimental for the mu opioid receptor affinity. Introduction of an arylalkoxy group at C-4 does not increase mu affinity in the case of benzyloxy, while a phenylpropoxy group reduces mu affinity. The delta and kappa affinities were also reduced compared to the reference compounds. A significant increase in the affinity at the mu opioid receptors was achieved by introducing a 14-phenylpropoxy group. Increases in the affinity at delta and kappa receptors were also observed. These findings provide further evidence that the nature of the substituent at position 14 has a major impact on the abilities of morphinans to interact with opioid receptors. In the [(35)S]GTPgammaS binding assay, all tested compounds were partial agonists at mu and delta receptors. Compounds 8 and 17 showed antagonism at kappa receptors, while compound 7 exhibited some partial agonist activity at this receptor. The novel derivatives of cyprodime containing a 14-phenylpropoxy group acted as potent antinociceptives. When tested in vivo, compounds 7, 8, and 17 were considerably more potent than morphine, with phenol 7 showing the highest antinociceptive potency (21-fold in the hot plate test, 38-fold in the tail flick test, and 300-fold in the paraphenylquinone writhing test) in mice. Introduction of a 14-phenylpropoxy substituent leads to a profound alteration in the pharmacological profile of this class of compounds.