Mediation of mitochondrial translocator protein by tanshinone ⅡA in apoptosis of HepG2 cells / 中国药理学通报

Aim To investigate the role of mitochondrial translocator protein(TSPO)in the apoptosis of HepG2 cells induced by tanshinone IIA(Tan II A)and the involved mechanism. Methods Following the HepG2 cells treated with Tan ⅡA at 2.5, 5 and 10 μmol·L-1, the cell viability was determined by MTT assay, and intracellular ATP content was determined by luciferin-luciferase method. Oxygen utilization was measured polarographically with a Clark oxygen electrode. Cell apoptosis was determined by Hoechst 33342 staining and flow cytometry. The mitochondrial membrane potential was assessed with JC-1 staining. The intracellular distribution of TSPO was examined by TSPO immunostaining, and the expressions of TSPO, Cyto C, caspase-3, caspase-9 were determined by immunoblotting analysis. Results Tan II A inhibited the proliferation of HepG2 cells in a dose-and time-dependent manner. The treatment with Tan II A inhibited ATP production and oxygen utilization of mitochondria. In addition, Tan ⅡA enhanced TSPO expression and accumulation in nuclei and up-regulated the expression of Cyto C, caspase-3 and caspase-9. Conclusions Tan II A induces the apoptosis of HepG2 cells, which may be related to the TSPO-mediated mitochondrial dysfunction.

Clinical Value of Translocator Protein Gene in Evaluating the Efficacy of FLT3-ITD/DNMT3A R882 Double-Mutated Acute Myeloid Leukemia / 中国实验血液学杂志

OBJECTIVE@#To observe the clinical significance of translocator proteins (TSPO) gene in the treatment of FLT3-ITD/DNMT3A R882 double-mutated acute myeloid leukemia (AML).@*METHODS@#Seventy-six patients with AML hospitalized in the Department of Hematology of the Affiliated People's Hospital of Ningbo University from June 2018 to June 2020 were selected, including 34 patients with FLT3-ITD mutation, 27 patients with DNMT3A R882 mutation, 15 patients with FLT3-ITD/DNMT3A R882 double mutation, as well as 19 patients with immune thrombocytopenia (ITP) hospitalized during the same period as control group. RNA was routinely extracted from 3 ml bone marrow retained during bone puncture, and TSPO gene expression was detected by transcriptome sequencing (using 2-deltadeltaCt calculation).@*RESULTS@#The expression of TSPO gene in FLT3-ITD group and DNMT3A R882 group at first diagnosis was 2.02±1.04 and 1.85±0.76, respectively, which were both higher than 1.00±0.06 in control group, but the differences were not statistically significant (P=0.671, P=0.821). The expression of TSPO gene in the FLT3-ITD/DNMT3A R882 group was 3.98±1.07, wich was significantly higher than that in the FLT3-ITD group and DNMT3A R882 group, the differences were statistically significant (P=0.032, P=0.021). The expression of TSPO gene in patients who achieved complete response after chemotherapy in the FLT3-ITD/DNMT3A R882 group was 1.19±0.87, which was significantly lower than that at first diagnosis, and the difference was statistically significant (P=0.011).@*CONCLUSION@#TSPO gene may be used as an indicator of efficacy in FLT3-ITD /DNMT3A R882 double-mutated AML.

Perspectives in TSPO PET Imaging for Neurologic Diseases / 대한핵의학회잡지

The translocator protein (18 kDa) (TSPO) is a mitochondrial transmembrane protein, which has brought attention as a neuroinflammatory biomarker. Positron emission tomography (PET) imaging studies have been done for several decades, since neuroinflammation has been implicated as an important pathophysiology of several common neurologic disorders. However, despite numerous previous studies with positive findings, its clinical significance is not yet clear. Various attempts to overcome the limitations are ongoing, in order to bring acceptance for use in clinics.

Effect of Translocator Protein Ligand YL-IPA08 on Anxiety-Depressive-Like Behavior in Postpartum Depression Rats / 中国药学杂志

OBJECTIVE: To study the effect of Mr1.8×104 translocator protein (TSPO) selective ligand compound YL-IPA08 on postpartum anxiety-depressive behavior. METHODS: The model of postpartum depression in rats was established by classical hormone simulating postpregnancy (HSP) hormone withdrawal induced, and the effect of YL-IPA08 on spontaneous activity in rats was evaluated by the open field test(OFT), and the effect of YL-IPA08 on anxiety and depressive-like behavior in rats was evaluated by the elevated plus maze test (EPM) and forced swimming test (FST). The changes of TSPO expression in hippocampuls and prefrontal cortex of rats were detected by RT-PCR and Western blot. RESULTS: Compared with control group, the hormones of pregnancy hormones withdraw stimulating and drug treatment do not affect the spontaneous activity of rats (P>0.05), but the model group rats showed significant anxiety and depressive symptoms, which is characterized by elevated plus maze test (P<0.05, P<0.01),and forced swimming test (P<0.05).After the establishment of the model, three weeks of intragastric administration were started, YL-IPA08 (0.1 and 0.3 mg•kg-1, po) or positive control drug sertraline (10 mg•kg-1, po) can significantly reverse the above series of changes of postpartum anxiety and depressive behavior (P<0.05 or 0.01), and significantly increase the TSPO level in the hippocampus and prefrontal cortex of the model rats. CONCLUSION: YL-IPA08 shows anti-postpartum anxiety-depressive behavior in a series of rat behavior models, and the mechanism may be closely related to its enhancing central TSPO expression and promoting biosynthesis of following neurosteroids.

Strategy for development of fast-onset antidepressive agents: Candidate hypothesis of monoamine (5-HT)-nonmonoamine (Glu/GABA) long-feedback neural circuit / 中国药理学与毒理学杂志

Depression has become a serious global public health concern. Almost all the current first-line antidepressants developed are based on the classical "monoamine hypothesis (strategy)". These drugs commonly possess a series of defects, including slow-onset, lower response, cognitive injury and suicidal tendencies. So, by breaking through the classical monoamine strategy framework, developing new antidepressants with fast-onset, cognitive-enhancement and less adverse reactions is a major global demand. In 2019, fast-onset antidepressants S-ketamine(S-Ket) and brexanolone were approved by the FDA of USA, which opened up a new field for the non-monoamine strategy mainly based on the N-methyl-D-aspartic acid (NMDA) and y-aminobutyric acid A (GABAA) receptors. There are currently two main trends in the research and development of rapid onset antidepressants: the optimized multi-target monoamine strategy (modem monoamine strategy) and the non-monoamine strategy based on glutamate(Glu)-GABA balance regulation. According to the research of our laboratory and foreign colleagues, we propose a candidate hypothesis of the "monoamine (5-HT)-nonmonoamine (Glu/ GABA) long feedback neural circuit". It is believed that both monoamine regulatory mechanisms (such as 5-HT neurons located in raphe nucleus) and non-monoamine regulatory mechanisms (Glu/GABA neurons located in the prefrontal cortex and other brain regions) are all part of the rapid-acting antidepressant mechanisms, and both of them form a long-feedback neural loop mediating the fast synaptogenesis of the brain regions including the prefrontal cortex and hippocampus. Based on this hypothesis, we propose five candidate strategies for rapid onset of antidepressant development. (1) By relieving the inhibition of GABA interneurons on glutamatergic pyramidal neurons or directly activating glutamatergic pyramidal neurons, the rapid excitation/inhibition (E/l) balance can be achieved; (2) simultaneous regulation of 5-HT neuronal activity and E/l balance by 5-HT transporter and 5-HT receptors such as 5-HT1A (that means simultaneous enhancement of monoamine and nonmonoamine links); (3) direct activation of mammalian sirolimus (rapamycin) target protein complex 1 (mTORCI) and rapid enhance ment of the brain- derived neurotrophic factor (BDNF)- mTOR signaling; (4) stimulation of the fast release of BDNF in the brain; (5) positive allosteric modulator of GABAA receptor. We hope that these ideas and strategies will bring about a breakthrough for the development of a new generation of antidepressants in China in the future, and provide useful reference for further discovery of candidate targets for rapid antidepressant therapy.

The relationship between the reverse shock index multiplied by GlasgowComa scale score and serum translocator protein and prognosis in patients with severe traumatic brain injury / 中华急诊医学杂志

Objective To investigate the value of the reverse shock index multiplied by GlasgowComa scale score (rSIG) and serum translocator protein 18000 in the prognosis of patients with severe traumatic brain injury. Methods One hundred and fifteen patients with severe traumatic brain injury were divided into the survival group and death group. SPSS 20.0 software was used to compare the vital signs, rSIG and TSPO between the two groups, and the relationship between rSIG and TSPO was analyzed. Receiver operating characteristic (ROC) curve was used to predict the value of rSIG and TSPO and their combination in the prognosis of patients with severe traumatic brain injury. According to the best cut-off value of rSIG and TSPO of ROC curve, patients were divided into the rSIG ≤ 14.8 group and rSIG>14.8 group, and the TSPO ≤ 1.84 ng/mL group and TSPO>1.84 ng/mL group, and the mortality between the groups was compared. Results In 115 patients, rSIG of the survival group was significantly higher than that of the death group, and TSPO was significantly lower than that of the death group [(10.5±4.4) vs. (6.4±4.1), 1.0(0.3,1.9) ng/mL vs.3.4 (2.0, 4.6) ng/mL, P<0.01]. The ability of rSIG combined with TSPO to forecast the mortality of patients with severe traumatic brain injury is not superior to the predictive power of these two indicators alone. The serum TSPO value and 28-day mortality in the rSIG > 4.15 group were significantly higher than those in the rSIG ≤ 4.15 group. The rSIG value of the TSPO ≤ 1.84 ng/mL group was significantly higher than that of the TSPO>1.84 ng/mL group; the 28-day mortality was significantly lower than that in the TSPO>1.84 ng/mL group. The rSIG value was negatively correlated with serum TSPO value (r=-0.611, P<0.01). Conclusions rSIG value and serum TSPO value have good predictive value for the prognosis of patients with severe traumatic brain injury, and can provide certain guiding significance in clinical practice.

Progress of microglial targeting PET imaging on translocator protein in Parkinson′s disease / 中华核医学与分子影像杂志

Neuroinflammation has been a key pathological process in many neurodegenerative disorders including Parkinson′s disease (PD), while the microglial activation is not only involved in but also regarded as a hallmark of the neuroinflammation. With PET, it has become possible to image in vivo the changes of microglia cells under different pathophysiological conditions. In this review, the basic theory of translocator protein (TSPO)-targeting PET (TSPO-PET) imaging is well described and its intriguing applications in PD are also elaborated.

Protective effect of selective 18 ku translocator protein ligand YL-IPA08 on BV-2 apoptosis induced by corticosterone / 中国药理学与毒理学杂志

OBJECTIVE To investigate the protective effect of selective 18 ku translocator protein (TSPO) ligand YL-IPA08 on corticosterone(CORT)-induced apoptosis of BV-2 cells and its potential mecha?nisms. METHODS BV-2 Cells were pretreated with selective TSPO ligand YL-IPA08 1-100 nmol · L-1 and(or) TSPO antagonist PK11195 100 nmol · L-1 for 2 h,and then co-incubated with CORT for another 24 h. The apoptosis rate was measured by flow cytometry. CCK-8 kit was used to test BV-2 cell viability. The protein expression of TSPO was determined by Western blotting. The level of allopreg?nanolone was detected by ELISA kit. RESULTS In line with positive drug-AC-5216, the cell apoptosis rate decreased in YL-IPA08 1-100 nmol · L-1 and CORT co-treatment groups(P<0.01), which was antago?nized by PK11195 100 nmol · L-1 treatment(P<0.05). Cell viability increased in YL-IPA08 100 nmol · L-1and CORT co-treatment groups (P<0.01), which was blocked by PK11195 100 nmol·L-1 treatment(P<0.01). The expression of TSPO and the level of allopregnanolone(P<0.01) were enhanced by YL-IPA08 100 nmol · L-1 pretreatment followed by CORT treatment. The enhancement of allopregnanolone level was blocked by PK11195 100 nmol·L-1 treatment(P<0.05). CONCLUSION YL-IPA08 can protect BV-2 cells from CORT induced apoptosis. The protective effect of YL-IPA08 may be conferred by the increasing level of TSPO expression and allopregnanolone.

Overexpression of 18 ku translocator protein in mouse hippocampal dentate gyrus mediates anxiety and depressive behavior / 中国药理学与毒理学杂志

OBJECTIVE To investigate the effect of overexpession of 18 ku translocator protein (TSPO) on the hippocampal dentate gyrus. METHODS Lentiviral (LV) vectors containing TSPO or the lentiviral sequence were infused into the hippocampus bilateral dentate gyri (2 × 108 TU · mL-1,1 μL per side)of mice. Behavioral tests were carried out. The anxiolytic-like behavior of mice was examined by such means as the elevated plus maze test , the staircase test , light dark box test for 12, 14 and 16 d, two behavioral despair models, tail suspension test and the forced swimming test for 16 and 18 d,respec?tively. Western blotting and ELISA were used to evaluate the TSPO expression and the concentration of allopregnanolone in hippocampal tissue (3 mm in diameter around the injection site on both sides) at the end of tests. RESULTS The results of behavioral experiments showed that TSPO overexpression group deneloped anxiolytic and antidepression-like behavior. LV-TSPO significantly increased the retention time in the central area〔14 ± 4 vs (25 ± 12)s,P<0.05〕. LV-TSPO significantly increased the percentage of entry into open arms entries percentage and the percentage of time spent in open arms time without changing total entries and total time in the elevated plus-maze test〔(13±8)%vs (26±18)%, P<0.05;(6 ± 6)%vs (27 ± 6)%, P<0.05)〕. LV-TSPO significantly decreased the number of rearings without changing the number of steps in staircase test (21±7 vs 12±5,P<0.05). LV-TSPO increased entries into the light area and retention time in light-dark transition test〔(18 ± 8)% vs (26 ± 7)%, P<0.05;72 ± 36 vs (191 ± 90)s, P<0.05)〕but significantly decreased immobility time in the tail suspension test and forced swimming test〔94±33 vs (36±20)s, P<0.01;137±36 vs (90±37)s, P<0.05)〕, without excitatory or inhibitory actions on the central nervous system. At the same time, the level of TSPO expression in hippocampal tissues (3 mm in diameter around the injection site on both sides) was significantly increased, so did the concentration of allopregnanolone (P<0.05). CONCLUSION Overexpression of TSPO in the hippocamus dentate gyrus of mice can induce anxiolytic and antidepressant-like behavior, and the downstream allo?pregnanolone biosynthesis at least partially mediates the behavioral effects.

Recent Progress in the Development of TSPO PET Ligands for Neuroinflammation Imaging in Neurological Diseases / 대한핵의학회잡지

Neuroinflammation is heavily associated with various neurological diseases including Alzheimer's disease, Parkinson's disease, multiple sclerosis, and stroke. It is strongly characterized by the activation of microglia which can be visualized using position emission tomography (PET). Traditionally, translocator protein 18 kDa (TSPO) has been the preferred target for imaging the inflammatory progression of the microglial component. TSPO is expressed in the outer mitochondrial membrane and present in very low concentrations in the healthy human brain, but is markedly upregulated in response to brain injury and inflammation. Due to its value as a marker of microglial activation and subsequent utility for evaluating neuroinflammation in CNS disorders, several classes of TSPO radioligands have been developed and evaluated. However, the application of these second-generation TSPO radiotracers has been subject to several limiting factors, including a polymorphism that affects TSPO binding. This review focuses on recent developments in TSPO imaging, as well as current limitations and suggestions for future directions from a medical imaging perspective.

Translocator protein mediated anti-PTSD effects of YL-IPA08 / 军事医学

Objective To explore the role of 18 ku translocator protein (TSPO) in the anti-post-traumatic-stress-disorder(PTSD) effects of YL-IPA08 and the value of TSPO as a potential pharmacological target using gene knock out mice.Methods The PCR method was used to genotype TSPO wild type (WT) mice and knock out (KO) mice.Foot shock was used to establish a well-accepted mouse model of PTSD,the open field test (OFT) was used to evaluate the locomotor activity in mice,and freezing measurement was used to evaluate the PTSD-like fear behavior in mice.Results Compared with TSPO WT mice,KO mice had no expressible TSPO gene,but showed similar locomotor activity to WT mice after PTSD modeling.On day 1,day 5 and day 16 after PTSD modeling (day-1-day 0),both WT and KO mice showed significant PTSD-like behavior with enhanced freezing time.However,8 d treatment (day 0-day 7) of YL-IPA08 (0.3 mg/kg,once daily) or positive drug sertraline (15 mg/kg,once daily) after PTSD modeling significantly reduced freezing time selectively in WT mice,but not in KO mice.Conclusion It has been found for the first time that TSPO WT and KO mice can show the same sensitivity to PTSD modeling (namely the same PTSD-like behavior performance).Interestingly,TSPO can mediate the anti-PTSD effects of YL-IPA08.Therefore,the present study provides direct evidence for the value of TSPO as an potential pharmacological target for PTSD.

Anti-post-traumatic-stress-disorder effects of YL-IPA08, a selective 18kDa translocator protein ligand / 国际药学研究杂志

Objective To explore the anti-post-traumatic-stress-disorder(anti-PTSD)effects of YL-IPA08,a selective 18kDa translocator protein(TSPO)ligand.Methods The time-dependent stress sensitization(TDS)method was used to establish a rat mod?el of PTSD.The open field test(OFT)was used to evaluate the locomotor activity in rats.The contextual freezing(CF)measurement, elevated plus maze(EPM)test and novel objective recognition(NOR)test were used to evaluate the PTSD-like behaviors in rats.The concentration of allopregnanolone in rat hippocampus was detected by ELISA. Results Compared with the control group,neither TDS nor drug treatment affected the locomotor activity in rats(P>0.05).However,PTSD rats showed significant PTSD-like behaviors with enhanced CF time in CF mearsurement,decreased open arm time and open arm entries in EPM test,and dropped object recogni?tion index in NOR test(P<0.05 or 0.01).Moreover,the concentration of hippocampus allopregnanolone was decreased in PTSD rats (P<0.05).YL-IPA08(0.05-0.1mg/kg)or positive drug sertraline(15 mg/kg),administered intragastrically after establishment of PTSD model,significantly reversed the above PTSD-like behavioral changes(P<0.05 or 0.01)and increased the concentration of hip?pocampus allopregnanolone in PTSD rats.Conclusion YL-IPA08 could improve the PTSD-like behavior in rats,and the mechanism may be related to the increased allopregnanolone level in hippocampus.

Translocator protein 18ku: A potential new therapeutic target for anxiety in the future / 国际药学研究杂志

Anxiety is one of the psychiatric disorders. However, the pathogenesis of anxiety is still uncertain. Translocator protein (18×103, 18ku) (TSPO) ligands have been proved useful in the treatment of neurological and psychiatric disorders, especially anxiety. TSPO Ligands are promising candidates for fast-acting anxiolytic drugs with less severe side effects than benzodiazepines. This review summaries TSPO molecular structure, distribution, and its function of treating anxiety and illustrates the advantage of TSPO ligands in treating anxiety and its application prospect.

Etifoxine for Pain Patients with Anxiety

Etifoxine (etafenoxine, Stresam(R)) is a non-benzodiazepine anxiolytic with an anticonvulsant effect. It was developed in the 1960s for anxiety disorders and is currently being studied for its ability to promote peripheral nerve healing and to treat chemotherapy-induced pain. In addition to being mediated by GABA(A)alpha2 receptors like benzodiazepines, etifoxine appears to produce anxiolytic effects directly by binding to beta2 or beta3 subunits of the GABA(A) receptor complex. It also modulates GABA(A) receptors indirectly via stimulation of neurosteroid production after etifoxine binds to the 18 kDa translocator protein (TSPO) of the outer mitochondrial membrane in the central and peripheral nervous systems, previously known as the peripheral benzodiazepine receptor (PBR). Therefore, the effects of etifoxine are not completely reversed by the benzodiazepine antagonist flumazenil. Etifoxine is used for various emotional and bodily reactions followed by anxiety. It is contraindicated in situations such as shock, severely impaired liver or kidney function, and severe respiratory failure. The average dosage is 150 mg per day for no more than 12 weeks. The most common adverse effect is drowsiness at the initial stage. It does not usually cause any withdrawal syndromes. In conclusion, etifoxine shows less adverse effects of anterograde amnesia, sedation, impaired psychomotor performance, and withdrawal syndromes than those of benzodiazepines. It potentiates GABA(A) receptor-function by a direct allosteric effect and by an indirect mechanism involving the activation of TSPO. It seems promising that non-benzodiazepine anxiolytics including etifoxine will replenish shortcomings of benzodiazepines and selective serotonin reuptake inhibitors according to animated studies related to TSPO.

TSPO:new nomenclature for the peripheral benzodiazepine receptor and its role in the neuropsycopharmacology / 中国药理学通报

The early characterization of the diazepam-binding sites outside the brain led to their assignment as peripheralbenzodiazepine receptors, or PBRs, to distinguish them from the central benzodiazepine receptor.Although PBR is a widely used and accepted name in the scientific community,recent data regarding the structure and molecular function of this protein increasingly support renaming it to represent more accurately its subcellular role (or roles) and putative tissue-specific function (or functions). Translocator protein (18 ku,TSPO), is proposed as a new name, regardless of the subcellular localization of the protein. This review deals with the pharmacological, structural and molecular characterization of the PBR and its role in the neuropshcopharmacology.