Drug interactions with cannabinoids Antoniou, Tony; Bodkin, Jack; Ho, Joanne M-W
CMAJ. Canadian Medical Association journal,
2020-Mar-02, 2020-03-02, 20200302, Volume:
192, Issue:
9
Journal Article
Peer reviewed
Open access
Antoniou et al present several facts about drug interactions with cannabinoids. Among other things, cannabinoids can affect levels of other drugs. Cannabidiol inhibits CYP2C19, increasing levels of ...the active metabolite of clobazam threefold. Interactions with other drugs metabolized by CYP2C19 should be anticipated. Very high international normalized ratio levels and bleeding have been reported with combined used of warfarin and marijuana. A case reporting a threefold increase in tacrolimus levels following the addition of cannabidiol shows that CYP3A4/5 inhibition can also occur.
One challenge for synthetic biologists is the predictable tuning of genetic circuit regulatory components to elicit desired outputs. Gene expression driven by ligand-inducible transcription factor ...systems must exhibit the correct ON and OFF characteristics: appropriate activation and leakiness in the presence and absence of inducer, respectively. However, the dynamic range of a promoter (i.e., absolute difference between ON and OFF states) is difficult to control. We report a method that tunes the dynamic range of ligand-inducible promoters to achieve desired ON and OFF characteristics. We build combinatorial sets of AraC-and LasR-regulated promoters containing -10 and -35 sites from synthetic and Escherichia coli promoters. Four sequence combinations with diverse dynamic ranges were chosen to build multi-input transcriptional logic gates regulated by two and three ligand-inducible transcription factors (LacI, TetR, AraC, XylS, RhlR, LasR, and LuxR). This work enables predictable control over the dynamic range of regulatory components.
Oral anticoagulants (OACs) are very commonly prescribed for prevention of serious vascular events, but are also associated with serious medication-related bleeding. Mitigation of harm is believed to ...require high-quality OAC management. This study aimed to identify barriers and facilitators for optimal OAC management from the perspective of patients, caregivers and healthcare providers. Using a qualitative descriptive study design, we conducted five focus groups, three with patients and caregivers and two with health care providers, in two health regions in Southwestern Ontario. An expert facilitator led the discussions using a semi-structured interview guide. Each session was digitally recorded, transcribed verbatim and anonymized. Transcripts were analyzed in duplicate using conventional content analysis. Forty-two (19 patients, 7 caregivers, and 16 providers including physicians, nurses and pharmacists) participated. More than half of the patients received OAC for the treatment of venous thromboembolism (57.9%) and the majority (94.7%) were on chronic therapy (defined as >3 years). Data analysis organized codes describing barriers and facilitators into 4 main themes-medication-related, patient-related, provider-related, and system-related. Barriers highlighted were problems with medication access due to cost, patient difficulties with adherence, knowledge and adjusting their lifestyles to OAC therapy, provider expertise, time for adequate communication amongst providers and their patients, and health care system inadequacies in supporting communications and monitoring. Facilitators identified generally addressed these barriers. Many barriers to optimal OAC management exist even in the era of DOACs, many of which are amenable to facilitators of improved care coordination, patient education, and adherence monitoring.
Abstract
Pyrrolysine (Pyl, O) exists in nature as the 22
nd
proteinogenic amino acid. Despite being a fundamental building block of proteins, studies of Pyl have been hindered by the difficulty and ...inefficiency of both its chemical and biological syntheses. Here, we improve Pyl biosynthesis via rational engineering and directed evolution of the entire biosynthetic pathway. To accommodate toxicity of Pyl biosynthetic genes in
Escherichia coli
, we also develop Alternating Phage Assisted Non-Continuous Evolution (Alt-PANCE) that alternates mutagenic and selective phage growths. The evolved pathway provides 32-fold improved yield of Pyl-containing reporter protein compared to the rationally engineered ancestor. Evolved PylB mutants are present at up to 4.5-fold elevated levels inside cells, and show up to 2.2-fold increased protease resistance. This study demonstrates that Alt-PANCE provides a general approach for evolving proteins exhibiting toxic side effects, and further provides an improved pathway capable of producing substantially greater quantities of Pyl-proteins in
E. coli
.
Adverse drug events (ADEs) are a leading cause of mortality, disability, and healthcare costs in older adults due to multimorbidity, age-related changes to pharmacology and polypharmacy.1, 2 ...Infographics have proliferated in health literature as an efficient, effective, and user-friendly means to convey complex information through the judicious application of text and visuals.3-5 Through a randomized controlled trial (RCT), we sought to develop geriatric drug infographics (GDIs) and evaluate their potential to improve clinician pharmacotherapy learning to mitigate ADEs in older, medically complex, and frail adults.
Selenocysteine (Sec) is naturally incorporated into proteins by recoding the stop codon UGA. Sec is not hardwired to UGA, as the Sec insertion machinery was found to be able to site‐specifically ...incorporate Sec directed by 58 of the 64 codons. For 15 sense codons, complete conversion of the codon meaning from canonical amino acid (AA) to Sec was observed along with a tenfold increase in selenoprotein yield compared to Sec insertion at the three stop codons. This high‐fidelity sense‐codon recoding mechanism was demonstrated for Escherichia coli formate dehydrogenase and recombinant human thioredoxin reductase and confirmed by independent biochemical and biophysical methods. Although Sec insertion at UGA is known to compete against protein termination, it is surprising that the Sec machinery has the ability to outcompete abundant aminoacyl‐tRNAs in decoding sense codons. The findings have implications for the process of translation and the information storage capacity of the biological cell.
The selenocysteine insertion machinery was engineered to recode multiple sense codons. This was demonstrated for Escherichia coli formate dehydrogenase and recombinant human thioredoxin reductase. In the picture the canonical genetic code table is overlaid with a single assay in which purple‐colored cells express active Sec‐containing enzymes.
We tested the substrate range of four wild-type E. coli aminoacyl-tRNA synthetases (AARSs) with a library of nonstandard amino acids (nsAAs). Although these AARSs could discriminate efficiently ...against the other canonical amino acids, they were able to use many nsAAs as substrates. Our results also show that E. coli tryptophanyl-tRNA synthetase (TrpRS) and tyrosyl-tRNA synthetase have overlapping substrate ranges. In addition, we found that the nature of the anticodon sequence of tRNA(Trp) altered the nsAA substrate range of TrpRS; this implies that the sequence of the anticodon affects the TrpRS amino acid binding pocket. These results highlight again that inherent AARS polyspecificity will be a major challenge in the aim of incorporating multiple different amino acids site-specifically into proteins.
Improved memory devices for synthetic cells Ho, Joanne M L; Bennett, Matthew R
Science (American Association for the Advancement of Science),
04/2018, Volume:
360, Issue:
6385
Journal Article
Peer reviewed
CRISPR enables efficient recording of signaling events in cells onto DNA
Synthetic biologists have long sought to make cells more like computers. This is not because they think cells will be more ...efficient than silicon—current microelectronics make excellent computers and are less messy than cell cultures—but instead because synthetic cells can interface with biology to perform biochemical tasks. Synthetic cells might one day be capable of attacking tumors or releasing site-specific drugs inside the human body. But to carry out these tasks, synthetic biologists must be able to program cells much in the same way we program computers—by providing them with decision-making capabilities based on inputs. Indeed, prototypes of many of the genetic parts necessary for turning cells into biocomputers have been constructed, including transcriptional logic gates (
1
), timers (
2
,
3
), counters (
4
), memory devices (
5
,
6
), tunable sensors (
7
,
8
), and even in vitro DNA systems that can perform complex calculations (
9
). On page 169 of this issue, Tang and Liu (
10
) expand the capabilities of cellular computers by engineering a new memory device that records events directly onto DNA.
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