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Escrig JI, Hahn HJ, Debnath A. Activity of Auranofin against Multiple Genotypes of Naegleria fowleri and Its Synergistic Effect with Amphotericin B In Vitro. ACS Chem Neurosci 2020; 11:2464-2471. [PMID: 32392039 DOI: 10.1021/acschemneuro.0c00165] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Primary amebic meningoencephalitis, caused by brain infection with a free-living ameba, Naegleria fowleri, leads to extensive inflammation of the brain and death within 3-7 days after symptoms begin. Treatment of primary amebic meningoencephalitis relies on amphotericin B in combination with other drugs, but use of amphotericin B is associated with severe adverse effects. Despite a fatality rate of over 97%, economic incentive to invest in development of antiamebic drugs by the pharmaceutical industry is lacking. Development of safe and rapidly acting drugs remains a critical unmet need to avert future deaths. Since FDA-approved anti-inflammatory and antiarthritic drug auranofin is a known inhibitor of selenoprotein synthesis and thioredoxin reductase and the genome of N. fowleri encodes genes for both selenocysteine biosynthesis and thioredoxin reductases, we tested the effect of auranofin against N. fowleri strains of different genotypes from the USA, Europe, and Australia. Auranofin was equipotent against all tested strains with an EC50 of 1-2 μM. Our growth inhibition study at different time points demonstrated that auranofin is fast-acting, and ∼90% growth inhibition was achieved within 16 h of drug exposure. A short exposure of N. fowleri to auranofin led to the accumulation of intracellular reactive oxygen species. This is consistent with auranofin's role in inhibiting antioxidant pathways. Further, combination of auranofin and amphotericin B led to 95% of growth inhibition with 2-9-fold dose reduction for amphotericin B and 3-20-fold dose reduction for auranofin. Auranofin has the potential to be repurposed for the treatment of primary amebic meningoencephalitis.
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Affiliation(s)
- Jose Ignacio Escrig
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0756, United States
| | - Hye Jee Hahn
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0756, United States
| | - Anjan Debnath
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093-0756, United States
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Amphotericin B Increases Transglutaminase 2 Expression Associated with Upregulation of Endocytotic Activity in Mouse Microglial Cell Line BV-2. Neurochem Res 2017; 42:1488-1495. [PMID: 28224343 DOI: 10.1007/s11064-017-2205-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 02/06/2017] [Accepted: 02/09/2017] [Indexed: 12/14/2022]
Abstract
Amphotericin B (AmB), a polyene antibiotic, is reported to cause the microglial activation to induce nitric oxide (NO) production and proinflammatory cytokines expression, and change neurotrophic factors expression in cultured microglia (Motoyoshi et al. in Neurochem Int 52:1290-1296, 2008). On the other hand, tissue-type transglutaminase (TG2) is involved in connection to phagocytes with apoptotic cells. Engulfment of neurons by activated microglia is thought to cause neurodegenerative diseases but detail is unclear, and involvement of TG2 in phagocytosis has been reported in our previous study using lipopolysaccharide-stimulated BV-2 cells (Kawabe et al. in Neuroimmunomodulation 22(4):243-249, 2015). In the present study, we examined the changes of TG2 expression, phagocytosis and pinocytosis in BV-2 cells stimulated by AmB. AmB stimulation increased TG2 expression and TG activity. Phagocytosis of dead cells and pinocytosis of fluorescent microbeads were also up-regulated by AmB stimulation in BV-2 cells. Blockade of TG activity by cystamine, an inhibitor of TGs, suppressed AmB-enhanced TG2 expression, TG activity, NO production, phagocytosis and pinocytosis. Excessive NO production from microglia and/or facilitation of phagocytosis might be involved in neuronal death. To control TG activity might make possible to protect neurons and care for CNS diseases.
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Nakajima H, Itakura M, Sato K, Nakamura S, Azuma YT, Takeuchi T. Extracellular poly(ADP-ribose) is a neurotrophic signal that upregulates glial cell line-derived neurotrophic factor (GDNF) levels in vitro and in vivo. Biochem Biophys Res Commun 2017; 484:385-389. [PMID: 28130107 DOI: 10.1016/j.bbrc.2017.01.129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 01/23/2017] [Indexed: 01/10/2023]
Abstract
Synthesis of poly(ADP-ribose) (PAR) is catalyzed by PAR polymerase-1 (PARP-1) in neurons. PARP1 plays a role in various types of brain damage in neurodegenerative disorders. In neurons, overactivation of PARP-1 during oxidative stress induces robust PAR formation, which depletes nicotinamide adenine dinucleotide levels and leads to cell death. However, the role of the newly-formed PAR in neurodegenerative disorders remains elusive. We hypothesized that the effects of PAR could occur in the extracellular space after it is leaked from damaged neurons. Here we report that extracellular PAR (EC-PAR) functions as a neuroprotective molecule by inducing the synthesis of glial cell line-derived neurotrophic factor (GDNF) in astrocytes during neuronal cell death, both in vitro and in vivo. In primary rat astrocytes, exogenous treatment with EC-PAR produced GDNF but not other neurotrophic factors. The effect was concentration-dependent and did not affect cell viability in rat C6 astrocytoma cells. Topical injection of EC-PAR into rat striatum upregulated GDNF levels in activated astrocytes and improved pathogenic rotation behavior in a unilateral 6-hydroxydopamine model of Parkinson disease in rats. These findings indicate that EC-PAR acts as a neurotrophic enhancer by upregulating GDNF levels. This effect protects the remaining neurons following oxidative stress-induced brain damage, such as that seen with Parkinson disease.
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Affiliation(s)
- Hidemitsu Nakajima
- Laboratory of Veterinary Pharmacology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58, Rinkuourai-kita, Izumisano, Osaka, 5988531, Japan.
| | - Masanori Itakura
- Laboratory of Veterinary Pharmacology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58, Rinkuourai-kita, Izumisano, Osaka, 5988531, Japan
| | - Keishi Sato
- Laboratory of Veterinary Pharmacology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58, Rinkuourai-kita, Izumisano, Osaka, 5988531, Japan
| | - Sunao Nakamura
- Laboratory of Veterinary Pharmacology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58, Rinkuourai-kita, Izumisano, Osaka, 5988531, Japan
| | - Yasu-Taka Azuma
- Laboratory of Veterinary Pharmacology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58, Rinkuourai-kita, Izumisano, Osaka, 5988531, Japan
| | - Tadayoshi Takeuchi
- Laboratory of Veterinary Pharmacology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58, Rinkuourai-kita, Izumisano, Osaka, 5988531, Japan
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Motoyoshi-Yamashiro A, Takano K, Kawabe K, Izawa T, Nakajima H, Moriyama M, Nakamura Y. Amphotericin B induces glial cell line-derived neurotrophic factor in the rat brain. J Vet Med Sci 2014; 76:1353-8. [PMID: 25283947 PMCID: PMC4221168 DOI: 10.1292/jvms.14-0160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Amphotericin B (AmB) is a
polyene antifungal drug and is reported to be one of a few reagents having therapeutic
effects on prion diseases, that is, a delay in the appearance of clinical signs and
prolongation of the survival time in an animal model. In prion diseases, glial cells have
been suggested to play important roles; however, the therapeutic mechanism of AmB on prion
diseases remains elusive. We have previously reported that AmB changed the expression of
neurotrophic factors in microglia and astrocytes (Motoyoshi et al., 2008,
Neurochem. Int. 52, 1290–1296; Motoyoshi-Yamashiro et
al., 2013, ibid. 63, 93–100). These results suggested that
neurotrophic factors derived from glial cells might be involved in the therapeutic
mechanism of AmB. In the present study, we examined immunohistochemically the effects of
AmB on the expression of neurotrophic factors in the rat brain. We found that direct
injection of AmB into the striatum significantly enhanced the expression of glial cell
line-derived neurotrophic factor protein. Amphotericin B also increased the expressions of
CD11b and glial fibrillary acidic protein, markers of microglia and astrocytes,
respectively. Moreover, expressions of the two neurotrophic factors by AmB were
co-localized with the expression of CD11b or glial fibrillary acidic protein. These
results suggest that AmB in vivo might also activate glial cells and
induce the production of neurotrophic factors protecting neurons in prion diseases.
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Affiliation(s)
- Akiko Motoyoshi-Yamashiro
- Laboratory of Integrative Physiology in Veterinary Sciences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka 598-8531, Japan
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Flexibilide obtained from cultured soft coral has anti-neuroinflammatory and analgesic effects through the upregulation of spinal transforming growth factor-β1 in neuropathic rats. Mar Drugs 2014; 12:3792-817. [PMID: 24979268 PMCID: PMC4113799 DOI: 10.3390/md12073792] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/28/2014] [Accepted: 05/29/2014] [Indexed: 12/27/2022] Open
Abstract
Chronic neuroinflammation plays an important role in the development and maintenance of neuropathic pain. The compound flexibilide, which can be obtained from cultured soft coral, possesses anti-inflammatory and analgesic effects in the rat carrageenan peripheral inflammation model. In the present study, we investigated the antinociceptive properties of flexibilide in the rat chronic constriction injury (CCI) model of neuropathic pain. First, we found that a single intrathecal (i.t.) administration of flexibilide significantly attenuated CCI-induced thermal hyperalgesia at 14 days after surgery. Second, i.t. administration of 10-μg flexibilide twice daily was able to prevent the development of thermal hyperalgesia and weight-bearing deficits in CCI rats. Third, i.t. flexibilide significantly inhibited CCI-induced activation of microglia and astrocytes, as well as the upregulated proinflammatory enzyme, inducible nitric oxide synthase, in the ipsilateral spinal dorsal horn. Furthermore, flexibilide attenuated the CCI-induced downregulation of spinal transforming growth factor-β1 (TGF-β1) at 14 days after surgery. Finally, i.t. SB431542, a selective inhibitor of TGF-β type I receptor, blocked the analgesic effects of flexibilide in CCI rats. Our results suggest that flexibilide may serve as a therapeutic agent for neuropathic pain. In addition, spinal TGF-β1 may be involved in the anti-neuroinflammatory and analgesic effects of flexibilide.
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