[Clinical Value of Translocator Protein Gene in Evaluating the Efficacy of FLT3-ITD/DNMT3A R882 Double-Mutated Acute Myeloid Leukemia].

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.

Assessing the potential anti-neuroinflammatory effect of minocycline in chronic low back pain: Protocol for a randomized, double-blind, placebo-controlled trial.

INTRODUCTION: Both preclinical studies, and more recent clinical imaging studies, suggest that glia-mediated neuroinflammation may be implicated in chronic pain, and therefore might be a potential treatment target. However, it is currently unknown whether modulating neuroinflammation effectively alleviates pain in humans. This trial tests the hypothesis that minocycline, an FDA-approved tetracycline antibiotic and effective glial cell inhibitor in animals, reduces neuroinflammation and may reduce pain symptoms in humans with chronic low back pain. METHODS AND ANALYSIS: This study is a randomized, double-blind, placebo-controlled clinical trial. Subjects, aged 18-75, with a confirmed diagnosis of chronic (≥ six months) low back pain (cLBP) and a self-reported pain rating of at least four out of ten (for at least half of the days during an average week) are enrolled via written, informed consent. Eligible subjects are randomized to receive a 14-day course of either active drug (minocycline) or placebo. Before and after treatment, subjects are scanned with integrated Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) using [11C]PBR28, a second-generation radiotracer for the 18 kDa translocator protein (TSPO), which is highly expressed in glial cells and thus a putative marker of neuroinflammation. Pain levels are evaluated via daily surveys, collected seven days prior to the start of medication, and throughout the 14 days of treatment. General linear models will be used to assess pain levels and determine the treatment effect on brain (and spinal cord) TSPO signal. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov (NCT03106740).

Safety, pharmacokinetics and pharmacodynamics of a novel γ-aminobutyric acid (GABA) receptor potentiator, HSK3486, in Chinese patients with hepatic impairment.

BACKGROUND: The primary objective of this study was to investigate if hepatic impairment alters the safety, pharmacokinetics, and pharmacodynamics of HSK3486. RESEARCH DESIGN AND METHODS: This was a clinical trial of HSK3486 in subjects with normal hepatic function (n = 8), and mild (Child-Pugh A; n = 8), or moderate (Child-Pugh B; n = 8) hepatic impairment. Each subject received an IV bolus dose of 0.4 mg/kg HSK3486 for 1 min, immediately followed by a maintenance infusion of 0.4 mg/kg/h HSK3486 for 30 min. RESULTS: In total, 24 subjects were enrolled and completed the study. HSK3486 was generally well tolerated by all subjects. There were no serious AEs and no deaths reported during the study. The incidence of AEs was numerically highest in subjects with moderate hepatic impairment. The exposure (AUC) of HSK3486 increased gradually with the decrease in hepatic function; however, degree of hepatic impairment had little effect on HSK3486 PD (MOAA/S and BIS). CONCLUSIONS: Overall, there were no clinically relevant differences in HSK3486 exposure or PD in subjects with mild or moderate hepatic impairment compared to normal control. These data imply that HSK3486 dose adjustment is not warranted in subjects with mild or moderate hepatic impairment. TRIAL REGISTRATION: The trial is registered at ClinicalTrials.gov (CT.gov identifier: NCT04145596).Key MessageHSK3486 at an IV bolus dose of 0.4 mg/kg and a maintenance infusion of 0.4 mg/kg/h was safe and well tolerated by all mild or moderate hepatic impairment subjects and normal hepatic function subjects.There were no clinically relevant differences in HSK3486 exposure or PD in subjects with mild or moderate hepatic impairment compared to subjects with normal hepatic function.HSK3486 dose adjustment is not required in subjects with mild or moderate hepatic impairment.

Neuroactive steroids - new possibilities in the treatment of postpartum depression.

Pregnancy and postpartum period are associated with demanding physical and psychological changes that often lead to the development of psychological disorders. Depression is diagnosed in more than one in six women after childbirth. However, the prevalence of postpartum depression can be much higher because many cases are undiagnosed. In the case of severe depression, the patient is switched to pharmacological treatment, with sertraline being the most commonly used for this diagnosis. A new drug used in the treatment of postpartum depression is brexanolone, which was registered by FDA in 2019. The advantage over conventional therapy is its rapid onset of action. The structure represents the neuroactive steroid - allopregnanolone, which acts as an agonist on the δ-subunit of the GABA receptor and improves the symptoms of postpartum depression. In addition to the registered brexanolone, another steroidal drug, zuranolone, is available in the third phase of the clinical trial. The steroid structure was chemically altered to improve bioavailability and create an oral dosage form. Another synthetic analogue of neuroactive allopregnanolone, known as ganaxolone, did not show a significant reduction in depressive symptoms in the second phase of the clinical trial compared to placebo. Nevertheless, it has great therapeutic potential in the treatment of various types of epilepsy.

Recent progress on the development of fluorescent probes targeting the translocator protein 18 kDa (TSPO).

The translocator protein 18 kDa (TSPO) was first identified in 1997, and has now become one of the appealing subcellular targets in medicinal chemistry and its related fields. TSPO involves in a variety of diseases, covering neurodegenerative diseases, psychiatric disorders, cancers, and so on. To date, various high-affinity TSPO ligands labelled with single-photon emission computed tomography (SPECT)/positron emission tomography (PET) radionuclides have been reported, with some third-generation radioligands advanced to clinical trials. On the other hand, only a few number of TSPO ligands have been labelled with fluorophores for disease diagnosis. It is noteworthy that the majority of the TSPO fluorescent probes synthesised to date are based on visible fluorophores, suggesting that their applications are limited to in vitro studies, such as in vitro imaging of cancer cells, post-mortem analysis, and tissue biopsies examinations. In this context, the potential application of TSPO ligands can be broadened for in vivo investigations of human diseases by labelling with near-infrared (NIR)-fluorophores or substituting visible fluorophores with NIR-fluorophores on the currently developed fluorescent probes. In this review article, recent progress on fluorescent probes targeting the TSPO are summarised, with an emphasis on development trend in recent years and application prospects in the future.

Inhibition of translocator protein 18 kDa suppressed the progression of glioma via the ELAV-like RNA-binding protein 1/MAPK-activated protein kinase 3 axis.

Glioma is the most common primary malignant brain tumors in adults. Despite considerable advances in treatment, the clinical outcome remains dismal. Translocator protein 18 kDa (TSPO), an evolutionarily conserved transmembrane protein, has always been found to be elevated in glioma, which predicts a poor prognosis. However, studies on the regulatory network of TSPO in glioma are limited. The Cancer Genome Atlas (TCGA) and our research group cohorts demonstrated that TSPO expression was also highly expressed in glioma tissues and glioma cell lines. Inhibition of TSPO expression significantly reduced glioma cell proliferation and mobility in vitro. Suppression of TSPO decreased the expression of MAPK-activated protein kinase 3 (MAPKAPK3) and increased the degradation rate of its mRNA. TSPO directly interacts with ELAV1-like RNA-binding protein 1 (HUR) and promotes the nuclear-cytoplasmic shuttling of HUR. Inhibition of HUR decreased MAPKAPK3 expression and cell proliferation and mobility, whereas overexpression of MAPKAPK3 reversed the effects. Overexpression of HUR in TSPO-knockdown cells enhanced the mRNA stability of MAPKAPK3. Furthermore, rescue experiments show that the HUR/MAPKAPK3 axis accounts for the TSPO-mediated effects on glioma cell proliferation and mobility. Together, our present study indicated that TSPO may promote the nuclear-cytoplasmic shuttling of HUR, thus increasing the mRNA stability of MAPKAPK3 and promoting the proliferation and mobility of glioma cells. The HUR/MAPKAPK3 axis may be key targets for blocking the effects of TSPO and may contribute to glioma therapy.

Molecular neuroimaging of inflammation in HIV.

People with HIV now have near-normal life expectancies due to the success of effective combination antiretroviral therapy (cART). Following cART initiation, immune recovery occurs, and opportunistic diseases become rare. Despite this, high rates of non-infectious comorbidities persist in treated people with HIV, hypothesized to be related to persistent immuno-activation. One such comorbidity is cognitive impairment, which may partly be driven by ongoing neuro-inflammation in otherwise effectively treated people with HIV. In order to develop therapeutic interventions to address neuro-inflammation in effectively treated people with HIV, a deeper understanding of the pathogenic mechanisms driving persistent neuro-inflammatory responses and the ability to better characterize and measure neuro-inflammation in the central nervous system is required. This review highlights recent advances in molecular neuroimaging techniques which have the potential to assess neuro-inflammatory responses within the central nervous system in HIV disease. Proton magnetic resonance spectroscopy (1H-MRS) has been utilized to assess neuro-inflammatory responses since early in the HIV pandemic and shows promise in recent studies assessing different antiretroviral regimens. 1H-MRS is widely available in both resource-rich and some resource-constrained settings and is relatively inexpensive. Brain positron emission tomography (PET) imaging using Translocator Protein (TSPO) radioligands is a rapidly evolving field; newer TSPO-radioligands have lower signal-to-noise ratio and have the potential to localize neuro-inflammation within the brain in people with HIV. As HIV therapeutics evolve, people with HIV continue to age and develop age-related comorbidities including cognitive disorders. The use of novel neuroimaging modalities in the field is likely to advance in order to rapidly assess novel therapeutic interventions and may play a role in future clinical assessments.

Association study of genetic polymorphisms in GABRD with treatment response and dose in methadone maintenance treatment.

Aim: This study determined if gene variants in the GABA receptor delta subunit (GABRD) are associated with treatment response and dose in methadone maintenance treatment (MMT) for heroin addiction. Materials & methods: A total of 286 MMT patients were recruited and divided into response and nonresponse groups based on retention time in therapy. A total of 177 responders were classified into low dose and high dose subgroups according to the stabilized methadone dose. Four (single nucleotide polymorphisms) SNPs (rs13303344, rs4481796, rs2376805 and rs2229110) in GABRD were genotyped using the TaqMan SNP assay. Logistic regression was used to assess the genetic effects of the SNPs in MMT. Results: No significant associations were observed between the SNPs and treatment response or dose, except the frequency of haplotype ACGC at the four SNPs significantly differed between responders and nonresponders. Conclusion: The results indicated that GABRD variants may play a small role in modulating methadone treatment response.

Lay abstract This study determined if gene variants in the GABA receptor delta subunit (GABRD) are associated with treatment response and dose in methadone maintenance treatment (MMT) for heroin addiction. A total of 286 MMT patients were recruited and divided into response and nonresponse groups. A total of 177 responders were classified into low and high dose subgroups. Four single nucleotide polymorphisms (SNPs) (rs13303344, rs4481796, rs2376805 and rs2229110) in GABRD were genotyped and assessed the genetic effects of the SNPs in MMT. No significant associations were observed between the SNPs and treatment response or dose, except the frequency of haplotype ACGC significantly differed between responders and nonresponders. The results indicated that GABRD variants may play a small role in MMT, which may help provide a foundation for personalized solutions for MMT.

Neuroprotective effect of mitochondrial translocator protein ligand in a mouse model of tauopathy.

BACKGROUND: The translocator protein (TSPO) has been identified as a positron emission tomography (PET)-visible biomarker of inflammation and promising immunotherapeutic target for the treatment of Alzheimer's disease (AD). While TSPO ligands have been shown to reduce the accumulation of the toxic Alzheimer's beta-amyloid peptide, their effect on tau pathology has not yet been investigated. To address this, we analyzed the effects of TSPO ligand, Ro5-4864, on the progression of neuropathology in rTg4510 tau transgenic mice (TauTg). METHODS: Brain atrophy, tau accumulation, and neuroinflammation were assessed longitudinally using volumetric magnetic resonance imaging, tau-PET, and TSPO-PET, respectively. In vivo neuroimaging results were confirmed by immunohistochemistry for markers of neuronal survival (NeuN), tauopathy (AT8), and inflammation (TSPO, ionized calcium-binding adaptor molecule 1 or IBA-1, and complement component 1q or C1q) in brain sections from scanned mice. RESULTS: TSPO ligand treatment attenuated brain atrophy and hippocampal neuronal loss in the absence of any detected effect on tau depositions. Atrophy and neuronal loss were strongly associated with in vivo inflammatory signals measured by TSPO-PET, IBA-1, and levels of C1q, a regulator of the complement cascade. In vitro studies confirmed that the TSPO ligand Ro5-4864 reduces C1q expression in a microglial cell line in response to inflammation, reduction of which has been shown in previous studies to protect synapses and neurons in models of tauopathy. CONCLUSIONS: These findings support a protective role for TSPO ligands in tauopathy, reducing neuroinflammation, neurodegeneration, and brain atrophy.

Targeting Mitochondria in Tumor-Associated Macrophages using a Dendrimer-Conjugated TSPO Ligand that Stimulates Antitumor Signaling in Glioblastoma.

Mitochondria mediate critical cellular processes, including proliferation, apoptosis, and immune responses; as such, their dysfunction is pathogenic in many neurodegenerative disorders and cancers. In glioblastoma, targeted delivery of mitochondria-focused anticancer therapies has failed to translate into clinical success due to the nonspecific cellular localization, heterogeneity of receptor expression across patients, poor transport across biological barriers to reach the brain, tumor, and mitochondria, and systemic side effects. Strategies that can overcome brain and solid tumor barriers and selectively target mitochondria within specific cell types may lead to improvements in glioblastoma treatment. Developments in dendrimer-mediated nanomedicines have shown promise targeting tumor-associated macrophages (TAMs) in glioblastoma, following systemic administration. Here, we present a novel dendrimer conjugated to the translocator protein (18 kDa) (TSPO) ligand 5,7-dimethylpyrazolo[1,5-α]pyrimidin-3-ylacetamide (DPA). We developed a clickable DPA for conjugation on the dendrimer surface and demonstrated in vitro that the dendrimer-DPA conjugate (D-DPA) significantly increases dendrimer colocalization with mitochondria. Compared to free TSPO ligand PK11195, D-DPA stimulates greater antitumor immune signaling. In vivo, we show that D-DPA targets mitochondria specifically within TAMs following systemic administration. Our results demonstrate that dendrimers can achieve TAM-specific targeting in glioblastoma and can be further modified to target specific intracellular compartments for organelle-specific drug delivery.

Diagnostic and Therapeutic Potential of TSPO Studies Regarding Neurodegenerative Diseases, Psychiatric Disorders, Alcohol Use Disorders, Traumatic Brain Injury, and Stroke: An Update.

Neuroinflammation and cell death are among the common symptoms of many central nervous system diseases and injuries. Neuroinflammation and programmed cell death of the various cell types in the brain appear to be part of these disorders, and characteristic for each cell type, including neurons and glia cells. Concerning the effects of 18-kDa translocator protein (TSPO) on glial activation, as well as being associated with neuronal cell death, as a response mechanism to oxidative stress, the changes of its expression assayed with the aid of TSPO-specific positron emission tomography (PET) tracers' uptake could also offer evidence for following the pathogenesis of these disorders. This could potentially increase the number of diagnostic tests to accurately establish the stadium and development of the disease in question. Nonetheless, the differences in results regarding TSPO PET signals of first and second generations of tracers measured in patients with neurological disorders versus healthy controls indicate that we still have to understand more regarding TSPO characteristics. Expanding on investigations regarding the neuroprotective and healing effects of TSPO ligands could also contribute to a better understanding of the therapeutic potential of TSPO activity for brain damage due to brain injury and disease. Studies so far have directed attention to the effects on neurons and glia, and processes, such as death, inflammation, and regeneration. It is definitely worthwhile to drive such studies forward. From recent research it also appears that TSPO ligands, such as PK11195, Etifoxine, Emapunil, and 2-Cl-MGV-1, demonstrate the potential of targeting TSPO for treatments of brain diseases and disorders.

TSPO ligand PK11195 improves Alzheimer-related outcomes in aged female 3xTg-AD mice.

Alzheimer's disease (AD) pathogenesis is a multifactorial process that involves numerous pathways within the central nervous system. Thus, interventions that interact with several disease-related pathways may offer an increased opportunity for successful prevention and treatment of AD. Translocator protein 18 kD (TSPO) is a mitochondrial protein that is associated with regulation of many cellular processes including inflammation, steroid synthesis, apoptosis, and mitochondrial respiration. Although TSPO ligands have been shown to be protective in several neurodegenerative paradigms, little work has been done to assess their potential as treatments for AD. Female 3xTg-AD mice were administered the TSPO ligand PK11195 once weekly for 5 weeks beginning at 16 months, an age characterized by extensive ß-amyloid pathology and behavioral impairments. Animals treated with PK11195 showed improvements in behavior and modest reductions of in both soluble and deposited ß-amyloid. The finding that short-term PK11195 treatment was effective in improving both behavioral and pathological outcomes in a model of late-stage AD supports further investigation of TSPO ligands as potential therapeutics for the treatment of AD.

Reversion of methacholine induced bronchoconstriction with inhaled diazepam in patients with asthma / Bloqueo de la respuesta bronco constrictora a metacolina con diazepam inhalado en pacientes con asma

Background: Benzodiazepines have a direct bronchodilatory effect. Methacholine is a non-selective muscarinic receptor agonist causing bronchoconstriction. Aim: To examine the effects of inhaled benzodiazepines, modulating bronchoconstriction induced by methacholine in patients with asthma. Patients and Methods: Twelve patients with well controlled asthma were studied. On the first day, after determining the initial values of pulmonary function, a dose response curve was carried out with progressive doses of methacholine. After the last dose, when at least a 20% drop of the initial forced expiratory volume in the first second (FEV1) was achieved, vital capacity (VC) and FEV1 were measured at 7, 15 and 30 minutes after provocation. On the second day a diazepam aerosol was inhaled by the patients prior to the same protocol with methacholine. Results: In the first day of testing, methacholine inhalation (6 mg/mL) led to a significant drop in FEV1 from 2.98 to 1.69 L. On the second day of study, in the same patients, previous inhalation with diazepam reduced the changes of FEV1 after inhalation of methacholine. This parameter decreased from 2.48 to 2.21 L. Conclusions: Inhalation of benzodiazepines reduce bronchoconstriction after a methacholine challenge in patients with asthma.

Antecedentes: Las benzodiacepinas tienen un efecto broncodilatador directo. La metacolina es un agonista muscarínico que causa bronco constricción. Objetivo: Evaluar el efecto modulador de la inhalación de diazepam sobre la bronco constricción inducida por metacolina. Pacientes y Métodos: Se estudiaron 12 pacientes con asma bien controlada. En el primer día, se determinó la curva dosis respuesta de parámetros de función pulmonar a una dosis progresiva de metacolina. Después de la última dosis, cuando se consiguió un 20% de reducción en la capacidad vital forzada en el primer segundo (FEV1), se midió FEV1 y la capacidad vital (CV) a los 7, 15 y 30 min después de la provocación. En el segundo día los pacientes se inhalaron con diazepam antes de hacer la prueba con metacolina. Resultados: En el primer día, el FEV1 bajo de 2,98 a 1,69 l con 6 mg/ml de metacolina. En el segundo día, la inhalación de diazepam redujo la respuesta a metacolina con una reducción de FEV1 de 2,48 a 2,21 L. Conclusiones: La benzodiacepinas reducen la respuesta de vasoconstricción a metacolina.

Mitochondrial translocator protein (TSPO): From physiology to cardioprotection.

The mitochondrial translocator protein (TSPO) is a high affinity cholesterol binding protein which is primarily located in the outer mitochondrial membrane where it has been shown to interact with proteins implicated in mitochondrial permeability transition pore (mPTP) formation. TSPO is found in different species and is expressed at high levels in tissues that synthesize steroids but is also present in other peripheral tissues especially in the heart. TSPO has been involved in the import of cholesterol into mitochondria, a key step in steroidogenesis. This constitutes the main established function of the protein which was recently challenged by genetic studies. TSPO has also been associated directly or indirectly with a wide range of cellular functions such as apoptosis, cell proliferation, differentiation, regulation of mitochondrial function or porphyrin transport. In the heart the role of TSPO remains undefined but a growing body of evidence suggests that TSPO plays a critical role in regulating physiological cardiac function and that TSPO ligands may represent interesting drugs to protect the heart under pathological conditions. This article briefly reviews current knowledge regarding TSPO and discusses its role in the cardiovascular system under physiological and pathologic conditions. More particularly, it provides evidence that TSPO can represent an alternative strategy to develop new pharmacological agents to protect the myocardium against ischemia-reperfusion injury.

Control of hypercholesterolemia and atherosclerosis using the cholesterol recognition/interaction amino acid sequence of the translocator protein TSPO.

The translocator protein (18-kDa) TSPO is an ubiquitous high affinity cholesterol-binding protein reported to be present in the endothelial and smooth muscle cells of the blood vessels; its expression dramatically increased in macrophages found in atherosclerotic plaques. A domain in the carboxy-terminus of TSPO was identified and characterized as the cholesterol recognition/interaction amino acid consensus (CRAC). The ability of the CRAC domain to bind to cholesterol led us to hypothesize that this peptide could be used as an hypocholesterolemic, with potential anti-atherogenic properties, agent. We report herein the therapeutic benefit that resulted for the administration of the VLNYYVWR human CRAC sequence to guinea pigs fed with a high cholesterol diet and ApoE knock-out B6.129P2-Apoetm1Unc/J mice. CRAC treatment (3 and 30mg/kg once daily for 6 weeks) resulted in reduced circulating cholesterol levels in guinea pigs fed with 2% high cholesterol diet and ApoE knock-out B6.129P2-Apoetm1Unc/J mice. In high cholesterol fed guinea pigs, CRAC treatment administered once daily induced an increase in circulating HDL, decreased total, free and LDL cholesterol, and removed atheroma deposits in the aorta in a dose-dependent manner. The treatment also prevented the high cholesterol diet-induced increase in serum creatine kinase, total and isoforms, markers of neurological, cardiac and muscular damage. No toxicity was observed. Taken together these results support a role of TSPO in lipid homeostasis and atherosclerosis and indicate that CRAC may constitute a novel and safe treatment of hypercholesterolemia and atherosclerosis.