CXCR4 and CCR5 expression by H9 T-cells is downregulated by a peptide-nucleic acid immunomodulator

The role of P2X7 receptor in infection and metabolism: Based on inflammation and immunity

The P2X7 receptor (P2X7R) is a ligand-gated receptor belonging to the P2 receptor family. It is distributed in various tissues of the human body and is involved in regulating the physiological functions of tissues and cells to affect the occurrence and development of diseases. Unlike all other P2 receptors, the P2X7 receptor is mainly expressed in immune cells and can be activated not only by extracellular nucleotides but also by non-nucleotide substances which act as positive allosteric modulators. In this review, we comprehensively describe the role of the P2X7 receptor in infection and metabolism based on its role as an important regulator of inflammation and immunity, and briefly introduce the structure and general function of the P2X7 receptor. These provide a clear knowledge framework for the study of the P2X7 receptor in human health. Targeting the P2X7 receptor may be an effective method for the treatment of inflammatory and immune diseases. And its role in microbial infection and metabolism may be the main direction for in-depth research on the P2X7 receptor in the future.

Phase II study of the novel peptide-nucleic acid OHR118 in the management of cancer-related anorexia/cachexia

BACKGROUND AND OBJECTIVE

OHR118 represents a new class of immunomodulatory and cytoprotective drugs in managing anorexia cachexia. Previously in patients with advanced HIV-AIDS, increases in appetite, strength, and alertness were noted. The objective was to determine the effect of OHR118 on appetite, early satiety, and nutritional intake in patients with advanced cancer. Secondary end points included changes in performance status, lean muscle mass, and quality of life (QOL).

METHODS

Eligible patients received 4.0 mL of OHR118 in subcutaneous daily injections. Patients underwent bi-monthly evaluations during the 28-day initial treatment (phase A). Evaluations included Karnofsky performance status, Edmonton Symptoms Assessment Scale (ESAS), Patient-Generated Subjective Global Assessment (PG-SGA), Simmonds Functional Assessment (SFA), Dyspepsia Symptom Severity Index (DSSI), weight, lean body mass, skin fold thickness, and grip strength. Patients who benefited from phase A could elect to continue with therapy (phase B).

RESULTS

Of 21 enrolled patients, 11 completed phase A. Eight patients chose to continue with OHR118 treatment (phase B). Weight stabilization or gain was observed in 7 of 11 patients. Total PG-SGA scores improved significantly (P ≤ .01). Appetite (P ≤ .01) and depression (P = .05) scores improved on ESAS. Frequent burping/belching (P = .02), feeling full (P = .04), and stomach distention (P = .03) improved on the DSSI. A deterioration in the timed sit to stand was noted (P = .01). OHR118 was well tolerated with no serious side effects reported.

CONCLUSIONS

OHR118 again mediated statistically significant improvements in anorexia, dyspepsia, strength, and depression in this trial, consonant with the previous AIDS trial results.

Fluorescence resonance energy transfer imaging reveals that chemokine-binding modulates heterodimers of CXCR4 and CCR5 receptors

Background

Dimerization has emerged as an important feature of chemokine G-protein-coupled receptors. CXCR4 and CCR5 regulate leukocyte chemotaxis and also serve as a co-receptor for HIV entry. Both receptors are recruited to the immunological synapse during T-cell activation. However, it is not clear whether they form heterodimers and whether ligand binding modulates the dimer formation.

Methodology/Principal Findings

Using a sensitive Fluorescence Resonance Energy Transfer (FRET) imaging method, we investigated the formation of CCR5 and CXCR4 heterodimers on the plasma membrane of live cells. We found that CCR5 and CXCR4 exist as constitutive heterodimers and ligands of CCR5 and CXCR4 promote different conformational changes within these preexisting heterodimers. Ligands of CCR5, in contrast to a ligand of CXCR4, induced a clear increase in FRET efficiency, indicating that selective ligands promote and stabilize a distinct conformation of the heterodimers. We also found that mutations at C-terminus of CCR5 reduced its ability to form heterodimers with CXCR4. In addition, ligands induce different conformational transitions of heterodimers of CXCR4 and CCR5 or CCR5^STA and CCR5^Δ4.

Conclusions/Significance

Taken together, our data suggest a model in which CXCR4 and CCR5 spontaneously form heterodimers and ligand-binding to CXCR4 or CCR5 causes different conformational changes affecting heterodimerization, indicating the complexity of regulation of dimerization/function of these chemokine receptors by ligand binding.

Randomized, placebo-controlled trial of product R, a peptide-nucleic acid immunomodulator, in the treatment of adults infected with HIV

OBJECTIVE

The efficacy of Product R, a nontoxic peptide-nucleic acid, was tested in 43 HIV-infected adults naïve to antiretroviral therapy.

METHOD

Patients were randomized to receive Product R (21 patients) or placebo (22 patients). Dosage was two 1 mL subcutaneous injections daily on days 1-14, followed by 1 mL daily on days 22-28, 36-42, and 50-56. The follow-up period lasted until day 120.

RESULTS

Mean root CD4 count increased in the Product R group during treatment and was significantly higher (p =.013) by the end of follow-up. Four Product R-treated patients, but none of the control patients, experienced declines in viral load of >0.5 log. At the end of follow-up, the Product R group experienced a mean weight increase (p =.003), whereas the placebo group experienced a mean weight loss. The number of deaths and opportunistic infections were lower in the Product R group than in the placebo group (p =.076). No toxic effects were observed in any of the patients administered Product R.

CONCLUSION

These findings suggest that Product R may have efficacy in the treatment of HIV-infected individuals.

Chemokine receptors: emerging opportunities for new anti-HIV therapies

The chemokine receptors CCR5 and CXCR4 are G-protein coupled receptors (GPCRs) of the immune system and the major co-receptors required for entry of HIV into CD4(+) target cells. CCR5 is critical for both human immunodeficiency virus (HIV) disease transmission and progression, whereas CXCR4 may be very important in late stages of disease. Additional co-receptors have been shown to function under certain conditions in vitro but evidence of supporting roles in HIV disease is currently lacking. The sheer number of co-receptors potentially used by HIV and the complexity of co-receptors usage are major challenges confronting usage of these molecules as drug development targets. Balanced against this, is a long history of success by the pharmaceutical industry in developing small molecule antagonists for many other classes of GPCRs. In this review, we discuss the current state of understanding of the co-receptor-based antiviral agents designed to block viral entry. The therapeutic potential of this field will be judged from future studies on the efficacy of these novel inhibitors in clinical trials. The data so far obtained from a number of studies point to the potential clinical use of this emerging class of therapeutic agents. Here we review current progress in co-receptor-based antiretroviral drug development and discuss the potential advantages and disadvantages of this approach.

IL-8 and MCP-1 secretion is enhanced by the peptide-nucleic acid immunomodulator, Product R, in U937 cells and primary human monocytes

Product R (Reticulose) is a peptide-nucleic acid immunomodulator recently shown to enhance the expression of mRNAs encoding pro-inflammatory cytokines. Interleukin 8 (IL-8) and macrophage chemoattractant protein-1 (MCP-1) are pro-inflammatory chemokines involved in immune cell mobilization and stimulation. To determine whether Product R acts by upregulating these chemokines, we assayed its effects on the expression of IL-8 and MCP-1 mRNAs and proteins by human monocytic U937 cells and by adherent peripheral blood mononuclear cells (PBMCs). U937 cells were cultured for 0-21 days in media containing 0-20% Product R or phosphate-buffered saline (PBS). Compared to control cultures, cells cultured in Product R expressed increased amounts of IL-8 and MCP-1 mRNAs, as measured by reverse transcriptase-polymerase chain reaction (RT-PCR). Product R also increased secretion of IL-8 and MCP-1, as measured by enzyme-linked immunosorbent assay (ELISA), and boosted secretion induced by bacterial lipopolysaccharide (LPS), in a time- and dose-dependent manner. In adherent PBMCs, Product R increased IL-8 and MCP-1 secretion, but reduced LPS-induced MCP-1 secretion. While mRNAs encoding the IL-8 receptor, CXCR2, and the MCP-1 receptor, CCR2, were increased in U937 cells cultured in 5-10% Product R, we observed no change in binding of receptor-specific antibodies. These findings suggest that Product R upregulates the expression of IL-8 and MCP-1, which may boost immune system activity in virally-infected patients.