The Emergence of the Old Drug Captagon as a New Illicit Drug: A Narrative Review.

First developed in the 1960s in Europe and approved briefly for use in the United States, fenethylline (sold as Captagon, one of its early trade names) is now a prominent drug of abuse in the Eastern Mediterranean Region. The drug was withdrawn from the United States market because of side effects that included hallucinations, visual distortions, and psychosis; it has also been linked to rare cases of myocardial infarction, seizures, and delusions. The chemical synthesis of fenethylline is straightforward and inexpensive. Manufactured in clandestine labs in Southern Europe and the Middle East, these amphetamines had been used by affluent Middle Eastern young people for recreation or study aids. Captagon has periodically emerged as a drug used in combat and conflict, and it was implicated in the 2015 riots in Paris. It has been described as "chemical courage" for combatants giving them focus, energy, and endurance in battle situations. Captagon is addictive but no cases of direct captagon-associated mortality have been reported. The use of drugs in war is nothing new, but captagon is also used heavily in the civilian population in war-torn areas to help them cope with food insecurity and maintain courage in dangerous situations. Captagon production and distribution drives the Syrian economy, but the drug's use is limited to certain regions and is rarely seen in North America. The drug is available online, but product may be contaminated with the inclusion of procaine, caffeine, or other substances.

From Antidepressant Tianeptine to Street Drug ZaZa: A Narrative Review.

Tianeptine is often incorrectly described as a selective serotonin reuptake inhibitor, but it actually is a µ-opioid receptor agonist with anxiolytic effects. It has been approved since the last 1980s in about 24 countries as a treatment for depression, but it was never cleared to market in the United States for this purpose. Nevertheless, tianeptine joined the billion-dollar US market of nootropics as ZaZa or Tianna Red and is widely available online and in small shops without a prescription, to the point that it has been nicknamed "gas station heroin." While the therapeutic dose range is about 25 to 50 mg/day, tianeptine abusers may take 100 times that amount. Tolerance occurs rapidly and users who seek to recapture the short-lived euphoric effects of the drug have to take more and more. Social media has peer-support sites for those trying to discontinue tianeptine. Tianeptine is associated with multiple side effects at high doses along with dependence, withdrawal symptoms, toxicity, respiratory depression, and even mortality. Agitation is more often a presenting symptom of withdrawal than toxicity. Tianeptine is often used by polysubstance drug abusers who may be unaware of the drug's dangers. Few clinicians are aware of tianeptine and most urine assays do not screen for it. Greater awareness is needed for this drug and steps must be taken as tianeptine or "gas station heroin" is emerging as a new public health threat.

RAS-dependent RAF-MAPK hyperactivation by pathogenic RIT1 is a therapeutic target in Noonan syndrome-associated cardiac hypertrophy.

RIT1 is a RAS guanosine triphosphatase (GTPase) that regulates different aspects of signal transduction and is mutated in lung cancer, leukemia, and in the germline of individuals with Noonan syndrome. Pathogenic RIT1 proteins promote mitogen-activated protein kinase (MAPK) hyperactivation; however, this mechanism remains poorly understood. Here, we show that RAF kinases are direct effectors of membrane-bound mutant RIT1 necessary for MAPK activation. We identify critical residues in RIT1 that facilitate interaction with membrane lipids and show that these are necessary for association with RAF kinases and MAPK activation. Although mutant RIT1 binds to RAF kinases directly, it fails to activate MAPK signaling in the absence of classical RAS proteins. Consistent with aberrant RAF/MAPK activation as a driver of disease, we show that pathway inhibition alleviates cardiac hypertrophy in a mouse model of RIT1 mutant Noonan syndrome. These data shed light on the function of pathogenic RIT1 and identify avenues for therapeutic intervention.

RASopathy mutations provide functional insight into the BRAF cysteine-rich domain and reveal the importance of autoinhibition in BRAF regulation.

BRAF is frequently mutated in human cancer and the RASopathy syndromes, with RASopathy mutations often observed in the cysteine-rich domain (CRD). Although the CRD participates in phosphatidylserine (PS) binding, the RAS-RAF interaction, and RAF autoinhibition, the impact of these activities on RAF function in normal and disease states is not well characterized. Here, we analyze a panel of CRD mutations and show that they increase BRAF activity by relieving autoinhibition and/or enhancing PS binding, with relief of autoinhibition being the major factor determining mutation severity. Further, we show that CRD-mediated autoinhibition prevents the constitutive plasma membrane localization of BRAF that causes increased RAS-dependent and RAS-independent function. Comparison of the BRAF- and CRAF-CRDs also indicates that the BRAF-CRD is a stronger mediator of autoinhibition and PS binding, and given the increased catalytic activity of BRAF, our studies reveal a more critical role for CRD-mediated autoinhibition in BRAF regulation.

The seventh international RASopathies symposium: Pathways to a cure-expanding knowledge, enhancing research, and therapeutic discovery.

RASopathies are a group of genetic disorders that are caused by genes that affect the canonical Ras/mitogen-activated protein kinase (MAPK) signaling pathway. Despite tremendous progress in understanding the molecular consequences of these genetic anomalies, little movement has been made in translating these findings to the clinic. This year, the seventh International RASopathies Symposium focused on expanding the research knowledge that we have gained over the years to enhance new discoveries in the field, ones that we hope can lead to effective therapeutic treatments. Indeed, for the first time, research efforts are finally being translated to the clinic, with compassionate use of Ras/MAPK pathway inhibitors for the treatment of RASopathies. This biannual meeting, organized by the RASopathies Network, brought together basic scientists, clinicians, clinician scientists, patients, advocates, and their families, as well as representatives from pharmaceutical companies and the National Institutes of Health. A history of RASopathy gene discovery, identification of new disease genes, and the latest research, both at the bench and in the clinic, were discussed.