Methamphetamine binge administration dose-dependently enhanced negative affect and voluntary drug consumption in rats following prolonged withdrawal: role of hippocampal FADD

Deciphering the therapeutic potential of trimetazidine in rheumatoid arthritis via targeting mi-RNA128a, TLR4 signaling pathway, and adenosine-induced FADD-microvesicular shedding: In vivo and in silico study

Rheumatoid arthritis (RA) is a debilitating autoimmune condition characterized by chronic synovitis, joint damage, and inflammation, leading to impaired joint functionality. Existing RA treatments, although effective to some extent, are not without side effects, prompting a search for more potent therapies. Recent research has revealed the critical role of FAS-associated death domain protein (FADD) microvesicular shedding in RA pathogenesis, expanding its scope beyond apoptosis to include inflammatory and immune pathways. This study aimed to investigate the intricate relationship between mi-RNA 128a, autoimmune and inflammatory pathways, and adenosine levels in modulating FADD expression and microvesicular shedding in a Freund's complete adjuvant (FCA) induced RA rat model and further explore the antirheumatoid potency of trimetazidine (TMZ). The FCA treated model exhibited significantly elevated levels of serum fibrogenic, inflammatory, immunological and rheumatological diagnostic markers, confirming successful RA induction. Our results revealed that the FCA-induced RA model showed a significant reduction in the expression of FADD in paw tissue and increased microvesicular FADD shedding in synovial fluid, which was attributed to the significant increase in the expression of the epigenetic miRNA 128a gene in addition to the downregulation of adenosine levels. These findings were further supported by the significant activation of the TLR4/MYD88 pathway and its downstream inflammatory IkB/NFB markers. Interestingly, TMZ administration significantly improved, with a potency similar to methotrexate (MTX), the deterioration effect of FCA treatment, as evidenced by a significant attenuation of fibrogenic, inflammatory, immunological, and rheumatological markers. Our investigations indicated that TMZ uniquely acted by targeting epigenetic miRNA128a expression and elevating adenosine levels in paw tissue, leading to increased expression of FADD of paw tissue and mitigated FADD microvesicular shedding in synovial fluid. Furthermore, the group treated with TMZ showed significant downregulation of TLR4/MYD88 and their downstream TRAF6, IRAK and NF-kB. Together, our study unveils the significant potential of TMZ as an antirheumatoid candidate, offering anti-inflammatory effects through various mechanisms, including modulation of the FADD-epigenetic regulator mi-RNA 128a, adenosine levels, and the TLR4 signaling pathway in joint tissue, but also attenuation of FADD microvesicular shedding in synovial fluid. These findings further highlight the synergistic administration of TMZ and MTX as a potential approach to reduce adverse effects of MTX while improving therapeutic efficacy.

Evaluating the daily modulation of FADD and related molecular markers in different brain regions in male rats

Fas-Associated protein with Death Domain (FADD), a key molecule controlling cell fate by balancing apoptotic versus non-apoptotic functions, is dysregulated in post-mortem brains of subjects with psychopathologies, in animal models capturing certain aspects of these disorders, and by several pharmacological agents. Since persistent disruptions in normal functioning of daily rhythms are linked with these conditions, oscillations over time of key biomarkers, such as FADD, could play a crucial role in balancing the clinical outcome. Therefore, we characterized the 24-h regulation of FADD (and linked molecular partners: p-ERK/t-ERK ratio, Cdk-5, p35/p25, cell proliferation) in key brain regions for FADD regulation (prefrontal cortex, striatum, hippocampus). Samples were collected during Zeitgeber time (ZT) 2, ZT5, ZT8, ZT11, ZT14, ZT17, ZT20, and ZT23 (ZT0, lights-on or inactive period; ZT12, lights-off or active period). FADD showed similar daily fluctuations in all regions analyzed, with higher values during lights off, and opposite to p-ERK/t-ERK ratios regulation. Both Cdk-5 and p35 remained stable and did not change across ZT. However, p25 increased during lights off, but exclusively in striatum. Finally, no 24-h modulation was observed for hippocampal cell proliferation, although higher values were present during lights off. These results demonstrated a clear daily modulation of FADD in several key brain regions, with a more prominent regulation during the active time of rats, and suggested a key role for FADD, and molecular partners, in the normal physiological functioning of the brain's daily rhythmicity, which if disrupted might participate in the development of certain pathologies.

Comparing the antidepressant-like effects of electroconvulsive seizures in adolescent and adult female rats: an intensity dose-response study

BACKGROUND

The induction of electroconvulsive seizures (ECS) in rodents induces sex- and age-specific disparities in antidepressant-like responses, with females and young age being the most unresponsive ones. Since the electrical charge needed to induce an effective convulsion is also altered by these variables, our aim was to compare different dose-intensities of ECS exclusively in female rats, since there is a lack of preclinical data characterizing this particular sex, while also evaluating efficacy during distinctive age periods of treatment (adolescence vs. adulthood).

METHODS

Adolescent and adult female Sprague-Dawley rats were exposed to an intensity dose-response study (55, 75 or 95 mA; 0.6 s, 100 Hz, 1 session/day, 5 days). The particular characteristics of the induced convulsions (tonic, clonic, recovery times) were monitored during treatment. Antidepressant-like responses were evaluated under the stress of the forced-swim test 1-, 3-, and 7-days post-treatment (i.e., improved immobility time as an indicative of an antidepressant-like response), and brains were collected 24 h later (8 days post-treatment) to evaluate potential changes in hippocampal neurogenesis (Ki-67 and NeuroD) by immunohistochemistry.

RESULTS

The lowest intensities tested of ECS (55 and 75 mA) induced an antidepressant-like effect in adult female rats, but rendered insufficient in adolescence. The lack of efficacy observed in adolescent rats paralleled differences in the characteristics of the seizures induced by ECS as compared to adulthood. In line with prior results, different dose-intensities of ECS modulated hippocampal neurogenesis in a comparable fashion with age (i.e., increased survival of neural progenitors 8 days post-treatment).

CONCLUSIONS

In conjunction, these results reinforce the importance of fine-tuning the parameters of ECS that might render efficacious while considering sex and age as essential variables for treatment response, and suggest that other molecular mechanisms, beside the partial role of hippocampal neurogenesis, might be participating in the antidepressant-like effects induced by ECS.

Methamphetamine: Mechanism of Action and Chinese Herbal Medicine Treatment for Its Addiction

With the proliferation of synthetic drugs, research on the mechanism of action of addictive drugs and treatment methods is of great significance. Among them, methamphetamine (METH) is the most representative amphetamine synthetic drug, and the treatment of METH addiction has become an urgent medical and social problem. In recent years, the therapeutic effects of Chinese herbal medicines on METH addiction have gained widespread attention because of their non-addictiveness, multiple targets, low side effects, low cost, and other characteristics. Previous studies have identified a variety of Chinese herbal medicines with effects on METH addiction. Based on the research on METH in recent years, this article summarizes the mechanism of action of METH as the starting point and briefly reviews the Chinese herbal medicine-based treatment of METH.

Time-dependent affective disturbances in abstinent patients with methylphenidate use disorder

BACKGROUND

Methylphenidate (MPH), also called Ritalin, is used to treat attention-deficit hyperactivity disorder (ADHD) patients. With occasional reports of subjects suffering from Methylphenidate use disorder (MPHUD), few studies analyzed the neuropsychological changes in this population.

PURPOSE

This study aims to evaluate the clinical outcomes of individuals with MPHUD.

METHODS

We retrospectively analyzed 61 MPH patients (aged 16-27 years) admitted to the Beijing Gaoxin Hospital drug rehabilitation program from Jan 2017 to Mar 2019. The drug use history and drug abuse motivation scale were collected at admission. Clinicians rated the Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale, and DSM-5 Stimulant use disorder criteria each week during the 4 weeks rehabilitation program. Correlation analyses were conducted between drug use history and affective disturbances.

RESULTS

The results showed that the adolescent period is the peak for MPH exposure, and 1/3 of patients got their first exposure to MPH from their parents. MPH abstinence accompanies severe anxiety and depression symptoms, significantly alleviating after four weeks of treatment.

CONCLUSIONS

MPHUD is associated with substantial affective disturbances, which warrants a more considerable sample investigation.

Goofballing of Opioid and Methamphetamine: The Science Behind the Deadly Cocktail

Globally, millions of people suffer from various substance use disorders (SUD), including mono-and polydrug use of opioids and methamphetamine. Brain regions such as the cingulate cortex, infralimbic cortex, dorsal striatum, nucleus accumbens, basolateral and central amygdala have been shown to play important roles in addiction-related behavioral changes. Clinical and pre-clinical studies have characterized these brain regions and their corresponding neurochemical changes in numerous phases of drug dependence such as acute drug use, intoxication, craving, withdrawal, and relapse. At present, many studies have reported the individual effects of opioids and methamphetamine. However, little is known about their combined effects. Co-use of these drugs produces effects greater than either drug alone, where one decreases the side effects of the other, and the combination produces a prolonged intoxication period or a more desirable intoxication effect. An increasing number of studies have associated polydrug abuse with poorer treatment outcomes, drug-related deaths, and more severe psychopathologies. To date, the pharmacological treatment efficacy for polydrug abuse is vague, and still at the experimental stage. This present review discusses the human and animal behavioral, neuroanatomical, and neurochemical changes underlying both morphine and methamphetamine dependence separately, as well as its combination. This narrative review also delineates the recent advances in the pharmacotherapy of mono- and poly drug-use of opioids and methamphetamine at clinical and preclinical stages.

MicroRNA-31-3p/RhoA signaling in the dorsal hippocampus modulates methamphetamine-induced conditioned place preference in mice

RATIONALE

MicroRNAs (miRNAs) regulate neuroplasticity-related proteins and are implicated in methamphetamine (METH) addiction. RhoA is a small Rho GTPase that regulates synaptic plasticity and addictive behaviors. Nevertheless, the functional relationship between RhoA and upstream miRNAs of METH addiction remains unclear.

OBJECTIVE

To explore the molecular biology and epigenetic mechanisms of the miR-31-3p/RhoA pathway in METH addiction.

METHODS

RhoA protein and its potential upstream regulator, miR-31-3p, were detected. A dual luciferase reporter was employed to determine whether RhoA constituted a specific target of miR-31-3p. Following adeno-associated virus (AAV)-mediated knockdown or overexpression of miR-31-3p or RhoA in the dorsal hippocampus (dHIP), mice were subjected to conditioned place preference (CPP) to investigate the effects of miR-31-3p and RhoA on METH-induced addictive behaviors.

RESULTS

RhoA protein was significantly decreased in the dHIP of CPP mice with a concomitant increase in miR-31-3p. RhoA was identified as a direct target of miR-31-3p. Knockdown of miR-31-3p in the dHIP was associated with increased RhoA protein and attenuation of METH-induced CPP. Conversely, overexpression of miR-31-3p was associated with decreased RhoA protein and enhancement of METH effects. Similarly, knockdown of RhoA in the dHIP enhanced METH-induced CPP, whereas RhoA overexpression attenuated the effects of METH. Parallel experiments using sucrose preference revealed that the effects of miR-31-3p/RhoA pathway modulation were specific to METH.

CONCLUSIONS

Our findings indicate that the miR-31-3p/RhoA pathway in the dHIP modulates METH-induced CPP in mice. Our results highlight the potential role of epigenetics represented by non-coding RNAs in the treatment of METH addiction.

Electroconvulsive seizures protect against methamphetamine-induced inhibition of neurogenesis in the rat hippocampus

Following methamphetamine consumption and during abstinence many behavioral consequences emerge (i.e., cognitive deficits, ongoing episodes of psychosis, depression, severe cravings, brain neurotoxicity), which are likely linked to propensity to relapse. In this line of thought, we recently showed that binge methamphetamine administration enhanced negative affect and voluntary drug consumption in rats, while it induced persistent neurotoxic effects (i.e., impaired hippocampal neurogenesis), effects that emerged long after drug removal. To date, no pharmacological strategies have been proven to be effective for the treatment of methamphetamine toxicity. A few studies have evaluated the impact of combining methamphetamine pretreatment with electroconvulsive seizures (ECS) post-treatment, an alternative non-pharmacological option used in psychiatry for resistant depression that offers a safe and really potent therapeutic response. Against this background, the present study aimed at testing whether repeated ECS treatment could ameliorate some of the long-term neurotoxicity effects induced by adolescent methamphetamine exposure in rats and emerging after drug removal. At the behavioral level, the main results showed that methamphetamine administration did not alter negative affect immediate during adolescence or later on in adulthood. Interestingly, repeated ECS improved the negative impact of methamphetamine administration on reducing hippocampal neurogenesis, demonstrating that ECS can attenuate certain degree of methamphetamine-induced neurotoxicity in rats, and suggesting ECS as a good therapeutical candidate that deserves further studies.

Increased negative affect when combining early-life maternal deprivation with adolescent, but not adult, cocaine exposure in male rats: regulation of hippocampal FADD

RATIONALE

Besides early drug initiation during adolescence, another vulnerability factor associated with increased risk for substance abuse later in life is early-life stress. One way of assessing such combined risk is by evaluating the emergence of increased negative affect during withdrawal (i.e., linked to persistence in drug seeking).

OBJECTIVES

To compare the impact of maternal deprivation with cocaine exposure at different ages on affective-like behavior and hippocampal neuroplasticity regulation.

METHODS

Maternal deprivation was performed in whole-litters of Sprague-Dawley rats (24 h, PND 9-10). Cocaine (15 mg/kg, 7 days, i.p.) was administered in adolescence (PND 33-39) or adulthood (PND 64-70). Changes in affective-like behavior were assessed by diverse tests across time (forced-swim, open field, novelty-suppressed feeding, sucrose preference). Hippocampal multifunctional FADD protein (balance between cell death and plasticity) was evaluated by Western blot.

RESULTS

Exposing rats to either maternal deprivation or adolescent cocaine did not modulate affective-like behavior immediately during adolescence, but increased negative affect in adulthood. Maternal deprivation combined with adolescent cocaine advanced the negative impact to adolescence. Adult cocaine exposure alone and/or in combination with maternal deprivation did not induce any behavioral changes at the time-points analyzed. FADD regulation might participate in the neural adaptations taking place in the hippocampus in relation to the observed behavioral changes.

CONCLUSIONS

Adolescence is a more vulnerable period, as compared to adulthood, to the combined impact of cocaine and early maternal deprivation, thus suggesting that the accumulation of stress early in life can anticipate the negative behavioral outcome associated with drug consumption.

Sex differences in the antidepressant-like potential of repeated electroconvulsive seizures in adolescent and adult rats: Regulation of the early stages of hippocampal neurogenesis

Age and sex are critical factors for the diagnosis and treatment of major depression, since there is a well-known age-by-sex difference in the prevalence of major depression (being females the most vulnerable ones) and in antidepressant efficacy (being adolescence a less responsive period than adulthood). Although the induction of electroconvulsive seizures (ECS) is a very old technique in humans, there is not much evidence reporting sex- and age-specific aspects of this treatment. The present study evaluated the antidepressant- and neurogenic-like potential of repeated ECS across time in adolescent and adult rats (naïve or in a model of early life stress capable of mimicking a pro-depressive phenotype), while including a sex perspective. The main results demonstrated age- and sex-specific differences in the antidepressant-like potential of repeated ECS, since it worked when administered during adolescence or adulthood in male rats (although with a shorter length in adolescence), while in females rendered deleterious during adolescence and ineffective in adulthood. Yet, repeated ECS increased cell proliferation and vastly boosted young neuronal survival in a time-dependent manner for both sexes and independently of age. Moreover, pharmacological inhibition of basal cell proliferation prevented the antidepressant-like effect induced by repeated ECS in male rats, but only partially blocked the very robust increase in the initial cell markers of hippocampal neurogenesis. Overall, the present results suggest that the induction of the early phases of neurogenesis by ECS, besides having a role in mediating its antidepressant-like effect, might participate in some other neuroplastic actions, opening the path for future studies.

Decreased sensitivity in adolescent versus adult rats to the antidepressant-like effects of cannabidiol

RATIONALE

Cannabidiol is a non-psychoactive phytocannabinoid with great therapeutic potential in diverse psychiatric disorders; however, its antidepressant potential has been mainly ascertained in adult rats.

OBJECTIVES

To compare the antidepressant-like response induced by cannabidiol in adolescent and adult rats and the possible parallel modulation of hippocampal neurogenesis.

METHODS

Male Sprague-Dawley rats were repeatedly treated with cannabidiol (3, 10, and 30 mg/kg) or vehicle (1 mL/kg) during adolescence (postnatal days, PND 27-33) or adulthood (PND 141-147) and exposed to 3 consecutive tests (forced swim, open field, two-bottle choice) that quantified behavioral despair, anxiety, and sucrose intake respectively.

RESULTS

Cannabidiol induced differential effects depending on the age and dose administered, with a decreased sensitivity observed in adolescent rats: (1) cannabidiol (30 mg/kg) decreased body weight only in adult rats; (2) cannabidiol ameliorated behavioral despair in adolescent and adult rats, but with a different dose sensitivity (10 vs. 30 mg/kg), and with a different extent (2 vs. 21 days post-treatment); (3) cannabidiol did not modulate anxiety-like behavior at any dose tested in adolescent or adult rats; and (4) cannabidiol increased sucrose intake in adult rats.

CONCLUSIONS

Our findings support the notion that cannabidiol exerts antidepressant- and anorexigenic-like effects in adult rats and demonstrate a decreased potential when administered in adolescent rats. Moreover, since cannabidiol did not modulate hippocampal neurogenesis (cell proliferation and early neuronal survival) in adolescent or adult rats, the results revealed potential antidepressant-like effects induced by cannabidiol without the need of regulating hippocampal neurogenesis.

Adolescent cocaine exposure enhanced negative affect following drug re-exposure in adult rats: Attenuation of c-Fos activation

BACKGROUND

The goal of the present study was to utilize the adolescent drug experience as an emerging vulnerability factor for developing psychiatric comorbidities in adulthood that could, in turn, help to elucidate and/or hypothesize possible mechanisms contributing to higher relapse rates.

OUTCOMES

The current results showed that adolescent cocaine exposure (15 mg/kg, intraperitoneally, seven days) during early-mid adolescence (postnatal days 33-39) enhanced negative affect in adulthood, by increasing behavioral despair following drug re-exposure and by increasing anhedonia. Thus, these behavioral data provided a good model to further ascertain the long-term cellular and molecular adaptations that might take place in the brain in response to adolescent cocaine exposure as well as the impact of drug re-exposure in adulthood. In this regard, the results showed that adolescent cocaine exposure did not modulate cell proliferation (Ki-67+ cells) or c-Fos protein activation in the dentate gyrus region of the hippocampus, but attenuated c-Fos activation in the dorsal striatum.

CONCLUSIONS

These results proved that a history of cocaine exposure during adolescence increased the vulnerability to induce negative affect (i.e. emergence of psychiatric comorbidity) in adulthood while it decreased neuronal activation in the dorsal striatum. Interestingly, these effects were only observed following cocaine re-exposure in adulthood, suggesting that avoiding drug contact in adulthood could prevent the long-term negative effects induced by adolescent cocaine.