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Two novel α7 nicotinic acetylcholine receptor ligands: in vitro properties and their efficacy in collagen-induced arthritis in mice.

van Maanen MA, Papke RL, Koopman FA, Koepke J, Bevaart L, Clark R, Lamppu D, Elbaum D, LaRosa GJ, Tak PP, Vervoordeldonk MJ - PLoS ONE (2015)

Bottom Line: Treatment with PMP-311 was effective in preventing disease onset, reducing clinical signs of arthritis, and reducing synovial inflammation and bone destruction.Finally, we found that the anti-arthritic effect can be observed despite limited penetration of the central nervous system.These data provide direct evidence that the α7nAChR in immune cells does not require typical ion channel activation to exert its antiinflammatory effects.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Immunology & Rheumatology, Academic Medical Center/University of Amsterdam, Amsterdam, The Netherlands.

ABSTRACT

Introduction: The cholinergic anti-inflammatory pathway can downregulate inflammation via the release of acetylcholine (ACh) by the vagus nerve. This neurotransmitter binds to the α7 subunit of nicotinic acetylcholine receptors (α7nAChR), expressed on macrophages and other immune cells. We tested the pharmacological and functional profile of two novel compounds, PMP-311 and PMP-072 and investigated their role in modulating collagen-induced arthritis (CIA) in mice.

Methods: Both compounds were characterized with binding, electrophysiological, and pharmacokinetic studies. For in vivo efficacy studies in the CIA model the compounds were administered daily by oral gavage from day 20 till sacrifice at day 34. Disease progression was monitored by visual clinical scoring and measurement of paw swelling. Inflammation and joint destruction were examined by histology and radiology.

Results: Treatment with PMP-311 was effective in preventing disease onset, reducing clinical signs of arthritis, and reducing synovial inflammation and bone destruction. PMP-072 also showed a trend in arthritis reduction at all concentrations tested. The data showed that while both compounds bind to α7nAChR with high affinity, PMP-311 acts like a classical agonist of ion channel activity, and PMP-072 can actually act as an ion channel antagonist. Moreover, PMP-072 was clearly distinct from typical competitive antagonists, since it was able to act as a silent agonist. It synergizes with the allosteric modulator PNU-120596, and subsequently activates desensitized α7nAChR. However, PMP-072 was less efficacious than PMP-311 at both channel activation and desensitization, suggesting that both conducting and non-conducting states maybe of importance in driving an anti-inflammatory response. Finally, we found that the anti-arthritic effect can be observed despite limited penetration of the central nervous system.

Conclusions: These data provide direct evidence that the α7nAChR in immune cells does not require typical ion channel activation to exert its antiinflammatory effects.

No MeSH data available.


Related in: MedlinePlus

Inhibition of bone degradation and reduction of synovial inflammation in murine collagen-induced arthritis at different doses of PMP-311 (n = 15) and PMP-072 (n = 15) given by oral gavage from day 20 until day 34.A, Semiquantitative scores for radiographic joint destruction of the knee joints. Joint destruction was significantly decreased in mice treated with PMP-311 2 mg/kg and 10 mg/kg compared to the control group. B, Semiquantitative scores for synovial inflammation, assessed by hematoxylin and eosin staining of the knee joints, showed a decrease of synovitis in mice treated with PMP-311 2 mg/kg and PMP-072 10 mg/kg. * P < 0.05 and ** P < 0.01 versus saline-treated mice.
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pone.0116227.g006: Inhibition of bone degradation and reduction of synovial inflammation in murine collagen-induced arthritis at different doses of PMP-311 (n = 15) and PMP-072 (n = 15) given by oral gavage from day 20 until day 34.A, Semiquantitative scores for radiographic joint destruction of the knee joints. Joint destruction was significantly decreased in mice treated with PMP-311 2 mg/kg and 10 mg/kg compared to the control group. B, Semiquantitative scores for synovial inflammation, assessed by hematoxylin and eosin staining of the knee joints, showed a decrease of synovitis in mice treated with PMP-311 2 mg/kg and PMP-072 10 mg/kg. * P < 0.05 and ** P < 0.01 versus saline-treated mice.

Mentions: Having shown proof of concept that PMP-311 treatment results in decreased arthritis activity, we next performed an independent dose-response study in mice with CIA. We tested the effects of PMP-311 in 1 lower and 1 higher dosage than used in study 1: 2 mg/kg and 10 mg/kg. Because PMP-072 showed a trend towards amelioration of clinical arthritis but was less potent in the receptor studies, we tested in the same experiment the effects of 2 higher doses: 10 mg/kg and 20 mg/kg. All of the animals tolerated the drug treatments well. To allow comparison with the results obtained in study 1, we calculated the percentages of the score compared to the control group. This experiment confirmed the beneficial effect of treatment with 5 mg/kg PMP-311 (a reduction of 49% in clinical score compared to saline (P < 0.05) (Fig. 5A)). Arthritis scores were also significantly lower after treatment with PMP-311 at either 2 mg/kg or 10 mg/kg with a reduction of 40% and 39%, respectively, compared to saline-treated mice (P < 0.01) (Fig. 5A). In the study where PMP-311 was administered at a dose of 2 mg/kg, there is a clear reduction of clinical score in the arthritic mice (p = 0.032). This decrease was mainly due to a decrease in inflammation since 14 out of 15 mice developed arthritis, These results suggest that all dosages were in the therapeutic range. The most pronounced effect of treatment on paw swelling was observed after low dose treatment (Fig. 5B). Of importance, treatment with PMP-311 2 mg/kg also resulted in a significant reduction in joint destruction (Fig. 6A) and synovial inflammation (Fig. 6B) compared with saline-treated mice (P < 0.01).


Two novel α7 nicotinic acetylcholine receptor ligands: in vitro properties and their efficacy in collagen-induced arthritis in mice.

van Maanen MA, Papke RL, Koopman FA, Koepke J, Bevaart L, Clark R, Lamppu D, Elbaum D, LaRosa GJ, Tak PP, Vervoordeldonk MJ - PLoS ONE (2015)

Inhibition of bone degradation and reduction of synovial inflammation in murine collagen-induced arthritis at different doses of PMP-311 (n = 15) and PMP-072 (n = 15) given by oral gavage from day 20 until day 34.A, Semiquantitative scores for radiographic joint destruction of the knee joints. Joint destruction was significantly decreased in mice treated with PMP-311 2 mg/kg and 10 mg/kg compared to the control group. B, Semiquantitative scores for synovial inflammation, assessed by hematoxylin and eosin staining of the knee joints, showed a decrease of synovitis in mice treated with PMP-311 2 mg/kg and PMP-072 10 mg/kg. * P < 0.05 and ** P < 0.01 versus saline-treated mice.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4305287&req=5

pone.0116227.g006: Inhibition of bone degradation and reduction of synovial inflammation in murine collagen-induced arthritis at different doses of PMP-311 (n = 15) and PMP-072 (n = 15) given by oral gavage from day 20 until day 34.A, Semiquantitative scores for radiographic joint destruction of the knee joints. Joint destruction was significantly decreased in mice treated with PMP-311 2 mg/kg and 10 mg/kg compared to the control group. B, Semiquantitative scores for synovial inflammation, assessed by hematoxylin and eosin staining of the knee joints, showed a decrease of synovitis in mice treated with PMP-311 2 mg/kg and PMP-072 10 mg/kg. * P < 0.05 and ** P < 0.01 versus saline-treated mice.
Mentions: Having shown proof of concept that PMP-311 treatment results in decreased arthritis activity, we next performed an independent dose-response study in mice with CIA. We tested the effects of PMP-311 in 1 lower and 1 higher dosage than used in study 1: 2 mg/kg and 10 mg/kg. Because PMP-072 showed a trend towards amelioration of clinical arthritis but was less potent in the receptor studies, we tested in the same experiment the effects of 2 higher doses: 10 mg/kg and 20 mg/kg. All of the animals tolerated the drug treatments well. To allow comparison with the results obtained in study 1, we calculated the percentages of the score compared to the control group. This experiment confirmed the beneficial effect of treatment with 5 mg/kg PMP-311 (a reduction of 49% in clinical score compared to saline (P < 0.05) (Fig. 5A)). Arthritis scores were also significantly lower after treatment with PMP-311 at either 2 mg/kg or 10 mg/kg with a reduction of 40% and 39%, respectively, compared to saline-treated mice (P < 0.01) (Fig. 5A). In the study where PMP-311 was administered at a dose of 2 mg/kg, there is a clear reduction of clinical score in the arthritic mice (p = 0.032). This decrease was mainly due to a decrease in inflammation since 14 out of 15 mice developed arthritis, These results suggest that all dosages were in the therapeutic range. The most pronounced effect of treatment on paw swelling was observed after low dose treatment (Fig. 5B). Of importance, treatment with PMP-311 2 mg/kg also resulted in a significant reduction in joint destruction (Fig. 6A) and synovial inflammation (Fig. 6B) compared with saline-treated mice (P < 0.01).

Bottom Line: Treatment with PMP-311 was effective in preventing disease onset, reducing clinical signs of arthritis, and reducing synovial inflammation and bone destruction.Finally, we found that the anti-arthritic effect can be observed despite limited penetration of the central nervous system.These data provide direct evidence that the α7nAChR in immune cells does not require typical ion channel activation to exert its antiinflammatory effects.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Immunology & Rheumatology, Academic Medical Center/University of Amsterdam, Amsterdam, The Netherlands.

ABSTRACT

Introduction: The cholinergic anti-inflammatory pathway can downregulate inflammation via the release of acetylcholine (ACh) by the vagus nerve. This neurotransmitter binds to the α7 subunit of nicotinic acetylcholine receptors (α7nAChR), expressed on macrophages and other immune cells. We tested the pharmacological and functional profile of two novel compounds, PMP-311 and PMP-072 and investigated their role in modulating collagen-induced arthritis (CIA) in mice.

Methods: Both compounds were characterized with binding, electrophysiological, and pharmacokinetic studies. For in vivo efficacy studies in the CIA model the compounds were administered daily by oral gavage from day 20 till sacrifice at day 34. Disease progression was monitored by visual clinical scoring and measurement of paw swelling. Inflammation and joint destruction were examined by histology and radiology.

Results: Treatment with PMP-311 was effective in preventing disease onset, reducing clinical signs of arthritis, and reducing synovial inflammation and bone destruction. PMP-072 also showed a trend in arthritis reduction at all concentrations tested. The data showed that while both compounds bind to α7nAChR with high affinity, PMP-311 acts like a classical agonist of ion channel activity, and PMP-072 can actually act as an ion channel antagonist. Moreover, PMP-072 was clearly distinct from typical competitive antagonists, since it was able to act as a silent agonist. It synergizes with the allosteric modulator PNU-120596, and subsequently activates desensitized α7nAChR. However, PMP-072 was less efficacious than PMP-311 at both channel activation and desensitization, suggesting that both conducting and non-conducting states maybe of importance in driving an anti-inflammatory response. Finally, we found that the anti-arthritic effect can be observed despite limited penetration of the central nervous system.

Conclusions: These data provide direct evidence that the α7nAChR in immune cells does not require typical ion channel activation to exert its antiinflammatory effects.

No MeSH data available.


Related in: MedlinePlus