Melatonin protects against oxidative stress in granular corneal dystrophy type 2 corneal fibroblasts by mechanisms that involve membrane melatonin receptors

Choi, Seung‐,Il,Dadakhujaev, Shorafidinkhuja,Ryu, Hyunmi,im Kim, Tae,Kim, Eung Kweon Blackwell Publishing Ltd 2011 Journal of pineal research Vol.51 No.1

<P><B>Abstract: </B> Considering that oxidative stress plays a role in corneal fibroblast degeneration during granular corneal dystrophy type 2 (GCD2) and melatonin is an effective antioxidant, we examined the ability of melatonin to protect against oxidative stress‐induced cell death of primary cultured normal and GCD2‐homozygous corneal fibroblasts. Melatonin treatment protected primary cultured normal and GCD2 corneal fibroblasts from paraquat (PQ)‐induced oxidative stress and caused increased expression levels of Cu/Zn‐superoxide dismutase (SOD1) and glutathione reductase (GR) in both types of cells. Interestingly, catalase expression increased in normal corneal fibroblasts, but decreased in GCD2 corneal fibroblasts after melatonin treatment. Melatonin also reduced the levels of intracellular reactive oxygen species and H<SUB>2</SUB>O<SUB>2</SUB> in both cell types. In addition, the selective melatonin receptor antagonist luzindole blocked melatonin‐induced expression of SOD1 and GR. The expression levels of melatonin receptors 1A (MT1) and 1B (MT2) were significantly higher in GCD2 corneal fibroblasts than in normal cells. These results suggest that increased expression of melatonin receptors may be involved in the defense mechanisms against oxidative stress in GCD2 corneal fibroblasts, and melatonin may have potential therapeutic implications for GCD2 treatment.</P>

두경부 암종세포에서 Luzindole을 이용한 YD15 세포와 HSC5 세포의 상피간엽이행 발현 변화 분석

장민아,김욱규,정승화,한혜연,유미현 대한구강악안면병리학회 2021 대한구강악안면병리학회지 Vol.45 No.1

Human melatonin receptors consist of melatonin receptor 1A (MT1) and melatonin receptor 1B (MT2), and possess various biological activations, which include the control of circadian rhythm and immune regulation. Recently, it have been found that melatonin receptors inhibit cell proliferation and have oncostatic properties, which is being researched in the treatment strategies of breast cancer, prostate cancer, and Non-Small Cell Lung Cancer. Also, interest in the effect of melatonin receptor’s correlation to head and neck carcinogenesis and application possibilities on head and neck cancer has been found. However, in head and neck cancer, how melatonin receptor relates and functions with epithelial-mesenchymal transition (EMT), which plays a major role in human carcinogenesis, is yet unknown. In this research, in HSC5 cell and YD15 cell, the head and neck cancer cell lines, a selective melatonin receptor antagonist, Luzindole, was utilized to examine the effect of melatonin receptors on EMT. After treating Luzindole on HSC5 cells and YD15 cells, the authors evaluated cell viability rate with CCK 8 assay, and performing colony forming assay, invasion assay and western blot analysis, to confirm melatonin receptor’s effect on EMT. When Luzindole was treated on HSC5 cells and YD15 cells in low concentration of 100nM, no significant difference in cell viability was found, whereas Luzindole-treated cells had a significantly increase in the invasion assay. As a result of colony forming assay, in YD15 cells, the number of colony formation decreased slightly, whereas in HSC3 cells, the number of colony formation increased. According to the western blotting, no difference in E-cadherin, Slug, and vimentin protein expression was shown. This result of research indicates the possibility of melatonin receptor being related to EMT and new chemotherapeutic target in the carcinogenesis of head and neck cancer.

The Expression Pattern of Melatonin Receptor 1a Gene during Early Life Stages in the Nile tilapia (Oreochromis niloticus)

Jin, Ye Hwa,Park, Jin Woo,Kim, Jung-Hyun,Kwon, Joon Yeong The Korean Society of Developmental Biology 2013 발생과 생식 Vol.17 No.1

The action of melatonin within the body of animals is known to be mediated by melatonin receptors. Three different types of melatonin receptors have been identified so far in fish. However, which of these are specifically involved in puberty onset is not known in fish. We cloned and analyzed the sequence of melatonin receptor 1a (mel 1a) gene in Nile tilapia Oreochromis niloticus. In addition, we examined the tissue distribution of gene expressions for three types of receptors, mel 1a, 1b and lc and investigated which of them is involved in the onset of puberty by comparing their expression with that of gonadotropin-releasing hormone receptor I (GnRHr I) gene using quantitative real-time PCR from 1 week post hatch (wph) to 24 wph. The mel 1a gene of Nile tilapia consisted of two exons and one bulky intron between them. Mel 1a gene was found to be highly conserved gene showing high homology with the corresponding genes from different teleost. All three types of melatonin receptor genes were expressed in the brain, eyes and ovary in common. Expression of mel 1a gene was the most abundant and ubiquitous among 3 receptors in the brain, liver, gill, ovary, muscle, eye, heart, intestine, spleen and kidney. Mel 1b and mel 1c genes were, however, expressed in fewer tissues at low level. During the development post hatch, expressions of both mel 1a and GnRHr I genes significantly increased at 13 wph which was close to the putative timing of puberty onset in this species. These results suggest that among three types of receptors mel 1a is most likely associated with the action of melatonin in the onset of puberty in Nile tilapia.

Effects of Placing Micro-Implants of Melatonin in Striatum on Oxidiative Stress and Neuronal Damage Mediated by N-Methyl-D-Aspartate (NMDA) and Non-NMDA Receptors

Kim, Hwa-Jung,Kwon, Jin-Suk The Pharmaceutical Society of Korea 1999 Archives of Pharmacal Research Vol.22 No.1

Overstimulation of both kainate (KA) and N-methyl-D-aspartate (NMDA) receptors has been reported to induce excitatoxicity which can be characterized by neuronal damage and formation of reactive oxygen free radicals. Neuroprotective effect of melatonin against KA-induced excitotoxicity have been documented in vitro and in vivo. It is, however, not clear whether melationin is also neuroportective against excitotoxicity mediated by NMDA receptors. In the present work, we tested the in vivo protective effects of striatally infused melatonin against the oxidative stress and neuronal damage induced by the injection of KA and NMDA receptors into the rat striatum. Melatonin implants consisting of 22-gauge stainless-steel cannule with melatonin fused inside the tip were placed bilaterally in the rat brain one week prior to intrastriatal injection of glutamate receptor subtype agonists. Melatonin showed protective effects against the elevation of lipid peroxidation induced by either KA or NMDA and recovered Cu, Zn-superoxide dismutase activities reduced by both KA and NMDA into the control level. Melatonin also clearly blocked both KA- and NMDA-receptor mediated neuronal damage assessed by the determination of choline acetyltransferase activity in striatal monogenages and by microscopic observation of rat brain section stained with cresyl violet. The protective effects of melatonin are comparable to those of DNQX and MK801 which are the KA- and NMDA-receptor antagonist, respectively. It is suggested that melatonin could protect against striatal oxidative damages mediated by glutamate receptors, both non-NMDA and NMDA receptors.

Melatonin Induces Akt Phosphorylation through Melatonin Receptor- and PI3K-Dependent Pathways in Primary Astrocytes

공필재,변종선,임소영,이재준,홍성준,권광준,김성수 대한약리학회 2008 The Korean Journal of Physiology & Pharmacology Vol.12 No.2

Melatonin has been reported to protect neurons from a variety of neurotoxicity. However, the underlying mechanism by which melatonin exerts its neuroprotective property has not yet been clearly understood. We previously demonstrated that melatonin protected kainic acid-induced neuronal cell death in mouse hippocampus, accompanied by sustained activation of Akt, a critical mediator of neuronal survival. To further elucidate the neuroprotective action of melatonin, we examined in the present study the causal mechanism how Akt signaling pathway is regulated by melatonin in a rat primary astrocyte culture model. Melatonin resulted in increased astrocytic Akt phosphorylation, which was significantly decreased with wortmannin, a specific inhibitor of PI3K, suggesting that activation of Akt by melatonin is mediated through the PI3K-Akt signaling pathway. Furthermore, increased Akt activation was also significantly decreased with luzindole, a non-selective melatonin receptor antagonist. As downstream signaling pathway of Akt activation, increased levels of CREB phoshorylation and GDNF expression were observed, which were also attenuated with wortmannin and luzindole. These results strongly suggest that melatonin exerts its neuroprotective property in astrocytes through the activation of plasma membrane receptors and then PI3K-Akt signaling pathway. Melatonin has been reported to protect neurons from a variety of neurotoxicity. However, the underlying mechanism by which melatonin exerts its neuroprotective property has not yet been clearly understood. We previously demonstrated that melatonin protected kainic acid-induced neuronal cell death in mouse hippocampus, accompanied by sustained activation of Akt, a critical mediator of neuronal survival. To further elucidate the neuroprotective action of melatonin, we examined in the present study the causal mechanism how Akt signaling pathway is regulated by melatonin in a rat primary astrocyte culture model. Melatonin resulted in increased astrocytic Akt phosphorylation, which was significantly decreased with wortmannin, a specific inhibitor of PI3K, suggesting that activation of Akt by melatonin is mediated through the PI3K-Akt signaling pathway. Furthermore, increased Akt activation was also significantly decreased with luzindole, a non-selective melatonin receptor antagonist. As downstream signaling pathway of Akt activation, increased levels of CREB phoshorylation and GDNF expression were observed, which were also attenuated with wortmannin and luzindole. These results strongly suggest that melatonin exerts its neuroprotective property in astrocytes through the activation of plasma membrane receptors and then PI3K-Akt signaling pathway.

The Expression Pattern of Melatonin Receptor 1a Gene during Early Life Stages in the Nile tilapia (Oreochromis niloticus)

진예화,Jin Woo Park,Jung-Hyun Kim,권준영 한국발생생물학회 2013 발생과 생식 Vol.17 No.1

The action of melatonin within the body of animals is known to be mediated by melatonin receptors. Three different types of melatonin receptors have been identified so far in fish. However, which of these are specifically involved in puberty onset is not known in fish. We cloned and analyzed the sequence of melatonin receptor 1a (mel 1a) gene in Nile tilapia Oreochromis niloticus. In addition, we examined the tissue distribution of gene expressions for three types of receptors, mel 1a, 1b and lc and investigated which of them is involved in the onset of puberty by comparing their expression with that of gonadotropin-releasing hormone receptor I (GnRHr I) gene using quantitative real-time PCR from 1 week post hatch (wph) to 24 wph. The mel 1a gene of Nile tilapia consisted of two exons and one bulky intron between them. Mel 1a gene was found to be highly conserved gene showing high homology with the corresponding genes from different teleost. All three types of melatonin receptor genes were expressed in the brain, eyes and ovary in common. Expression of mel 1a gene was the most abundant and ubiquitous among 3 receptors in the brain, liver, gill, ovary, muscle,eye, heart, intestine, spleen and kidney. Mel 1b and mel 1c genes were, however, expressed in fewer tissues at low level. During the development post hatch, expressions of both mel 1a and GnRHr I genes significantly increased at 13 wph which was close to the putative timing of puberty onset in this species. These results suggest that among three types of receptors mel 1a is most likely associated with the action of melatonin in the onset of puberty in Nile tilapia.

멜라토닌이 랫트에서 심박수에 미치는 영향

심소연,신세린,김진상,Shim, So-yeon,Shin, Se-rin,Kim, Jin-shang 대한수의학회 2001 大韓獸醫學會誌 Vol.41 No.4

Evidence from the last 10 years have been suggested that melatonin mainly produce a depressant effect on the cardiac system, but we found an activating effect of melatonin on heart rate in this research. To determine the hypothesis that melatonin has dual effects on physiological behaviour of cardiac system, we investigated the effects of melatonin on heart rate in isolated rat atria and anesthetized rats. Regardless of concentration, melatonin produced bradycardia in the 84 cases of 148 experiments (57 %) and tachycardia in the 64 cases of 148 experiments (43 %). And in atrium, melatonin produced a decrease automaticity in 52 cases of 86 experiments (60 %) and increase automaticity in 40 % (34/86 cases). Also, these effects are not significnat relationship with concetration of melatonin. The melatonin-induced bradycardia in vivo was inhibited by pretreatment of atropine or bilateral cervical vagotomy. Also, in isolated atrium the melatonin-induced decrease in automaticity was inhibited by pretreatment of atropine. These melatonin-induced responses were potenitated by pretreatment of propranolol. The melatonin-induced tachycardia in vivo was inhibited by pretreatment of propranolol, nifedipine or bilateral cervical vagotomy, but not by pretreatment of atropine. The melatonin-induced incease in automaticity in isolated atrium was converted to decrease in automaticity by pretreatment of propranolol. In addition, the change in heart rate caused by adrenoceptor agonists was inhibited by pretreatment of melatonin. These results indicate that melatonin-induced bradycardia may be related to a muscarinic receptor activation and melatonin-induced tachycardia may be related to a $\beta$-adrenoceptor stimulation.

Melatonin alleviates asphyxial cardiac arrest-induced cerebellar Purkinje cell death by attenuation of oxidative stress

Cho, Jeong Hwi,Tae, Hyun-Jin,Kim, In-Shik,Song, Minah,Kim, Hyunjung,Lee, Tae-Kyeong,Kim, Young-Myeong,Ryoo, Sungwoo,Kim, Dae Won,Lee, Choong-Hyun,Hwang, In Koo,Yan, Bing Chun,Kang, Il Jun,Won, Moo-Ho Academic Press 2019 Experimental neurology Vol.320 No.-

<P><B>Abstract</B></P> <P>Although multiple reports using animal models have confirmed that melatonin appears to promote neuroprotective effects following ischemia/reperfusion-induced brain injury, the relationship between its protective effects and activation of autophagy in Purkinje cells following asphyxial cardiac arrest and cardiopulmonary resuscitation (CA/CPR) remains unclear. Rats used in this study were randomly assigned to 6 groups as follows; vehicle-treated sham operated group, vehicle-treated asphyxial CA/CPR operated group, melatonin-treated sham operated group, melatonin-treated asphyxial CA/CPR operated group, PDOT (a MT2 melatonin receptor antagonist) plus (+) melatonin-treated sham operated group and PDOT+melatonin-treated asphyxial CA/CPR operated group. Melatonin (20 mg/kg, i.p., 4 times before CA and 3 times after CA) treatment significantly improved survival rate and neurological deficit compared with the vehicle-treated asphyxial CA/CPR rats (survival rates ≥40% vs 10%), showing that melatonin treatment exhibited protective effect against asphyxial CA/CPR-induced Purkinje cell death. The protective effect of melatonin against CA/CPR-induced Purkinje cell death paralleled a remarkable attenuation of autophagy-like processes (Beclin-1, Atg7 and LC3), as well as a dramatic reduction in superoxide anion radical (O<SUB>2</SUB>·-), intense enhancements of CuZn superoxide dismutase (SOD1) and MnSOD (SOD2) expressions. Furthermore, the protective effect was notably reversed by treatment with PDOT, which is a selective MT2 antagonist. In brief, melatonin conferred neuroprotection against asphyxial CA/CPR-induced Purkinje cell death via inhibiting autophagic activation by reducing expressions of O<SUB>2</SUB>·- and increasing expressions of antioxidant enzymes, and suggests that MT2 is involved in neuroprotective effect of melatonin against Purkinje cell death caused by asphyxial CA/CPR.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Melatonin prevents cerebellar Purkinje cell death following asphyxial cardiac arrest. </LI> <LI> Melatonin attenuates autophagy-like processes via MT2 receptor. </LI> <LI> Melatonin attenuates increase of superoxide anion radical via MT2 receptor. </LI> <LI> Melatonin maintains antioxidant enzymes expressions via MT2 receptor. </LI> </UL> </P>

Melatonin's protective action against ischemic neuronal damage is associated with up-regulation of the MT2 melatonin receptor

Lee, Choong Hyun,Yoo, Ki-Yeon,Choi, Jung Hoon,Park, Ok Kyu,Hwang, In Koo,Kwon, Young-Guen,Kim, Young-Myeong,Won, Moo-Ho Wiley Subscription Services, Inc., A Wiley Company 2010 Journal of neuroscience research Vol.88 No.12

<P>Melatonin is a potent free radical scavenger and antioxidant and has protective effects against ischemic damage. In the present study, we examined the relationship between the neuroprotective effects of melatonin and the activation of MT2 melatonin receptor in the hippocampal CA1 region (CA1) after transient cerebral ischemia. MT2 immunoreactivity and protein levels were increased in the CA1 after ischemic damage. Most of MT2-immunoreactive cells were colocalized with astrocytes, not microglia, in the ischemic CA1. In the melatonin-sham group, MT2 immunoreaction and protein levels were increased compared with the sham group, and MT2 immunoreactivity and its protein levels in the melatonin-ischemia group were similar to those in the melatonin-sham group. In addition, melatonin treatment attenuated the activation of astrocytes and microglia. These results indicate that MT2 are increased and expressed in astrocytes in the ischemic region after an ischemic insult. The activation of MT2 melatonin receptor in the CA1 after melatonin treatment may be involved in the neuroprotective effect associated with melatonin after ischemic injury. © 2010 Wiley-Liss, Inc.</P>

A Study for the Expression of Melatonin Receptor Gene and Reproductive Indices in Golden Hamsters Exposed to Photoperiods

Park Donchan,Park Hyungjae,Sinae Lim,Park Changeun 한국발생생물학회 2002 발생과 생식 Vol.6 No.1

골든 햄스터의 생식활동은 광주기에 의해 조절된다. 그들의 생식능력은 여름에 왕성하고 겨울에는 퇴화한다. 송과선에서 분비되는 멜라토닌은 계절적 번식동물에서 생식활동을 중재한다. 멜라토닌 수용체가 최근에 사람을 포함하는 몇몇 동물에서 확인되었지만 골든 햄스터의 생식능력과 관련하여 알려진 바가 많지 않다. 역전사 PCR 방법을 사용하여 멜라토닌 수용체의 일부 유전자를 동정하였다(309 염기). 멜라토닌 수용체의 핵산 서열과 추론된 아미노산 서열을 보고된 다른 Reproductive activity of golden hamsters(Mesocricetus auratus) is regulated by the photoperiod. They are sexually active in summer and inactive in winter. Melatonin, a pineal hormone, has been known to mediate sexual activities in seasonal breeding animals. Melatonin receptor was recently identified in several animal species including hmm. But little has been known about it in relation to the reproductive activities of golden hamsters. By using reverse transcription polymerase chain reaction(RT-PCR) methods, a portion of the melatonin receptor gene(309 nucleotides) was identified in golden hamsters. The nucleotide sequence of the melatonin receptor and the amino acid sequence deduced were compared to those reported in other animals. Melatonin receptors were obviously detected in hypothalamus, pituitary containing pars tuberalis, blood, and spleen. Although the testicular weights and the levels of reproductive hormones were dramatically affected by photoperiods, the expression of melatonin receptor was not markedly changed by them. These results suggest that the action of melatonin in regulating reproduction might be mainly due to the affinity of melatonin receptor rather than the density fi melatonin receptor.