Pharmacokinetics and a simulation model of colforsin daropate, new forskolin derivative inotropic vasodilator, in patients undergoing coronary artery bypass grafting

Construction and optimization of Saccharomyces cerevisiae for synthesizing forskolin

Forskolin, one of the primary active metabolites of labdane-type diterpenoids, exhibits significant medicinal value, such as anticancer, antiasthmatic, and antihypertensive activities. In this study, we constructed a Saccharomyces cerevisiae cell factory that efficiently produced forskolin. First, a chassis strain that can accumulate 145.8 mg/L 13R-manoyl oxide (13R-MO), the critical precursor of forskolin, was constructed. Then, forskolin was produced by integrating CfCYP76AH15, CfCYP76AH11, CfCYP76AH16, ATR1, and CfACT1-8 into the 13R-MO chassis with a titer of 76.25 μg/L. We confirmed that cytochrome P450 enzymes (P450s) are the rate-limiting step by detecting intermediate metabolite accumulation. Forskolin production reached 759.42 μg/L by optimizing the adaptations between CfCYP76AHs, t66CfCPR, and t30AaCYB5. Moreover, multiple metabolic engineering strategies, including regulation of the target genes' copy numbers, amplification of the endoplasmic reticulum (ER) area, and cofactor metabolism enhancement, were implemented to enhance the metabolic flow to forskolin from 13R-MO, resulting in a final forskolin yield of 21.47 mg/L in shake flasks and 79.33 mg/L in a 5 L bioreactor. These promising results provide guidance for the synthesis of other natural terpenoids in S. cerevisiae, especially for those containing multiple P450s in their synthetic pathways. KEY POINTS: • The forskolin biosynthesis pathway was optimized from the perspective of system metabolism for the first time in S. cerevisiae. • The adaptation and optimization of CYP76AHs, t66CfCPR, and t30AaCYB5 promote forskolin accumulation, which can provide a reference for diterpenoids containing complex pathways, especially multiple P450s pathways. • The forskolin titer of 79.33 mg/L is the highest production currently reported and was achieved by fed-batch fermentation in a 5 L bioreactor.

Progress in heterologous biosynthesis of forskolin

Forskolin, a class of labdane-type diterpenoid, has significant medicinal value in anticancer, antiasthmatic, antihypertensive, and heart-strengthening treatments. The main source of natural forskolin is its extraction from the cork tissue of the root of Coleus forskohlii. However, conventional modes of extraction pose several challenges. In recent years, the construction of microbial cell factories to produce medicinal natural products via synthetic biological methods has effectively solved the current problems and is a research hotspot in this field. This review summarizes the recent progress in the heterologous synthesis of forskolin via synthetic biological technology, analyzes the current challenges, and proposes corresponding strategies.

Current state and future perspective of cardiovascular medicines derived from natural products

The contribution of natural products (NPs) to cardiovascular medicine has been extensively documented, and many have been used for centuries. Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide. Over the past 40 years, approximately 50% of newly developed cardiovascular drugs were based on NPs, suggesting that NPs provide essential skeletal structures for the discovery of novel medicines. After a period of lower productivity since the 1990s, NPs have recently regained scientific and commercial attention, leveraging the wealth of knowledge provided by multi-omics, combinatorial biosynthesis, synthetic biology, integrative pharmacology, analytical and computational technologies. In addition, as a crucial part of complementary and alternative medicine, Traditional Chinese Medicine has increasingly drawn attention as an important source of NPs for cardiovascular drug discovery. Given their structural diversity and biological activity NPs are one of the most valuable sources of drugs and drug leads. In this review, we briefly described the characteristics and classification of NPs in CVDs. Then, we provide an up to date summary on the therapeutic potential and the underlying mechanisms of action of NPs in CVDs, and the current view and future prospect of developing safer and more effective cardiovascular drugs based on NPs.

High-titer production of 13R-manoyl oxide in metabolically engineered Saccharomyces cerevisiae

Background

Diterpenoids are a large class of natural products with complex structures and broad commercial applications as food additives, important medicines, and fragrances. However, their low abundance in plants and high structural complexity limit their applications. Therefore, it is important to create an efficient diterpenoid-producing yeast cell factory of the production of various high-value diterpenoid compounds in a cost-effective manner

Results

In this study, 13R-manoyl oxide (13R-MO; 2.31 mg/L) was produced by expressing CfTPS2 and CfTPS3 from Coleusforskohlii in Saccharomyces cerevisiae. The 13R-MO titer was increased by 142-fold to 328.15 mg/L via the stepwise metabolic engineering of the original strain, including the overexpression of the rate-limiting genes (tHMG1 and ERG20) of the mevalonate pathway, transcription and protein level regulation of ERG9, Bts1p and Erg20^F96Cp fusion, and the overexpression of tCfTPS2 and tCfTPS3 (excision of the N-terminal plastid transit peptide sequences of CfTPS2 and CfTPS3). The final titer of 13R-MO reached up to 3 g/L by fed-batch fermentation in a 5 L bioreactor.

Conclusions

In this study, an efficient 13R-MO yeast cell factory was constructed, which achieved the de novo production of 3 g/L of 13R-MO from glucose. To the best of our knowledge, this is the highest 13R-MO titer reported to date. Furthermore, the metabolic engineering strategies presented here could be used to produce other valuable diterpenoid compounds in yeast.

Electronic supplementary material

The online version of this article (10.1186/s12934-019-1123-z) contains supplementary material, which is available to authorized users.

Simultaneous Quantification of Forskolin and Iso-Forskolin in Coleus forskohlii (Wild.) Briq. and Identification of Elite Chemotype, Collected from Eastern Ghats (India)

Background:

Coleus forskohlii is a well-known industrially important medicinal plant, for its high forskolin content.

Objective:

A simple, selective, and sensitive high-performance thin layer chromatography (HPTLC) method was developed and validated for simultaneous quantification of forskolin and iso-forskolin in C. forskohlii germplasm collected from the Eastern Ghats, India.

Materials and Methods:

Chromatographic separation of the targeted marker(s) was obtained on precoated silica plates using toluene: ethyl acetate: methanol (90:30:0.5, v/v/v) as the mobile phase.

Results:

Densitometric quantification of forskolin and iso-forskolin was carried out at 545 nm. Forskolin and iso-forskolin were identified by comparing the ultraviolet spectra of standard and sample track at R_f of 0.64 ± 0.02 and 0.36 ± 0.01, after derivatization with anisaldehyde sulfuric acid reagent. The linearity of both the analytes was obtained in the range of 300–1200 ng/spot with the regression coefficient (R²) of 0.991 and 0.986. Recovery of analyte (s) at three levels, namely, 100, 150, and 200 ng/spot was found to be 100.46% ± 0.29%, 99.64% ± 0.33%, 100.02% ± 0.76% and 99.76% ± 0.62%, 99.56% ± 0.35%, 100.02% ± 0.22%, respectively, for forskolin and iso-forskolin. The content of forskolin and iso-forskolin varies from 0.046% to 0.187% and 0.002% to 0.077%, respectively (dry weight basis), the maximum content of both the markers was found in NBC-31, from Thakurwada, Maharashtra.

Conclusion:

The developed HPTLC method was linear, accurate, and reliable as per the International Council for Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use guidelines. The study aids in the identification of elite chemotype for commercial prospection of industrially viable medicinal crop.

SUMMARY

12 Samples are collected from different locations of the eastern ghat regions

Quantification of two major marker forskolin and iso forskolin

The maximum content of both the markers was found in NBC -31, from Thakurwada, Maharashtra

Identification of elite chemotype of collected samples may be useful for commercial prospection in industries.

Total biosynthesis of the cyclic AMP booster forskolin from Coleus forskohlii

Forskolin is a unique structurally complex labdane-type diterpenoid used in the treatment of glaucoma and heart failure based on its activity as a cyclic AMP booster. Commercial production of forskolin relies exclusively on extraction from its only known natural source, the plant Coleus forskohlii, in which forskolin accumulates in the root cork. Here, we report the discovery of five cytochrome P450s and two acetyltransferases which catalyze a cascade of reactions converting the forskolin precursor 13R-manoyl oxide into forskolin and a diverse array of additional labdane-type diterpenoids. A minimal set of three P450s in combination with a single acetyl transferase was identified that catalyzes the conversion of 13R-manoyl oxide into forskolin as demonstrated by transient expression in Nicotiana benthamiana. The entire pathway for forskolin production from glucose encompassing expression of nine genes was stably integrated into Saccharomyces cerevisiae and afforded forskolin titers of 40 mg/L.

The Natural cAMP Elevating Compound Forskolin in Cancer Therapy: Is It Time?

Cancer is a major public health problem and the second leading cause of mortality around the world. Although continuous advances in the science of oncology and cancer research are now leading to improved outcomes for many cancer patients, novel cancer treatment options are strongly demanded. Naturally occurring compounds from a variety of vegetables, fruits, and medicinal plants have been shown to exhibit various anticancer properties in a number of in vitro and in vivo studies and represent an attractive research area for the development of new therapeutic strategies to fight cancer. Forskolin is a diterpene produced by the roots of the Indian plant Coleus forskohlii. The natural compound forskolin has been used for centuries in traditional medicine and its safety has also been documented in conventional modern medicine. Forskolin directly activates the adenylate cyclase enzyme, that generates cAMP from ATP, thus, raising intracellular cAMP levels. Notably, cAMP signaling, through the PKA-dependent and/or -independent pathways, is very relevant to cancer and its targeting has shown a number of antitumor effects, including the induction of mesenchymal-to-epithelial transition, inhibition of cell growth and migration and enhancement of sensitivity to conventional antitumor drugs in cancer cells. Here, we describe some features of cAMP signaling that are relevant to cancer biology and address the state of the art concerning the natural cAMP elevating compound forskolin and its perspectives as an effective anticancer agent. J. Cell. Physiol. 232: 922-927, 2017. © 2016 Wiley Periodicals, Inc.

The natural compound forskolin synergizes with dexamethasone to induce cell death in myeloma cells via BIM

We have previously demonstrated that activation of the cyclic adenosine monophosphate (cAMP) pathway kills multiple myeloma (MM) cells both in vitro and in vivo. In the present study we have investigated the potential of enhancing the killing of MM cell lines and primary MM cells by combining the cAMP-elevating compound forskolin with the commonly used MM therapeutic drugs melphalan, cyclophosphamide, doxorubicin, bortezomib and dexamethasone. We observed that forskolin potentiated the killing induced by all the tested agents as compared to treatment with the single agents alone. In particular, forskolin had a synergistic effect on the dexamethasone-responsive cell lines H929 and OM-2. By knocking down the proapoptotic BCL-2 family member BIM, we proved this protein to be involved in the synergistic induction of apoptosis by dexamethasone and forskolin. The ability of forskolin to maintain the killing of MM cells even at lower concentrations of the conventional agents suggests that forskolin may be used to diminish treatment-associated side effects. Our findings support a potential role of forskolin in combination with current conventional agents in the treatment of MM.

Microbial Synthesis of the Forskolin Precursor Manoyl Oxide in an Enantiomerically Pure Form

Forskolin is a promising medicinal compound belonging to a plethora of specialized plant metabolites that constitute a rich source of bioactive high-value compounds. A major obstacle for exploitation of plant metabolites is that they often are produced in small amounts and in plants difficult to cultivate. This may result in insufficient and unreliable supply leading to fluctuating and high sales prices. Hence, substantial efforts and resources have been invested in developing sustainable and reliable supply routes based on microbial cell factories. Here, we report microbial synthesis of (13R)-manoyl oxide, a proposed intermediate in the biosynthesis of forskolin and other medically important labdane-type terpenoids. Process optimization enabled synthesis of enantiomerically pure (13R)-manoyl oxide as the sole metabolite, providing a pure compound in just two steps with a yield of 10 mg/liter. The work presented here demonstrates the value of a standardized bioengineering pipeline and the large potential of microbial cell factories as sources for sustainable synthesis of complex biochemicals.

Cyclic AMP synthesis and hydrolysis in the normal and failing heart

Cyclic AMP regulates a multitude of cellular responses and orchestrates a network of intracellular events. In the heart, cAMP is the main second messenger of the β-adrenergic receptor (β-AR) pathway producing positive chronotropic, inotropic, and lusitropic effects during sympathetic stimulation. Whereas short-term stimulation of β-AR/cAMP is beneficial for the heart, chronic activation of this pathway triggers pathological cardiac remodeling, which may ultimately lead to heart failure (HF). Cyclic AMP is controlled by two families of enzymes with opposite actions: adenylyl cyclases, which control cAMP production and phosphodiesterases, which control its degradation. The large number of families and isoforms of these enzymes, their different localization within the cell, and their organization in macromolecular complexes leads to a high level of compartmentation, both in space and time, of cAMP signaling in cardiac myocytes. Here, we review the expression level, molecular characteristics, functional properties, and roles of the different adenylyl cyclase and phosphodiesterase families expressed in heart muscle and the changes that occur in cardiac hypertrophy and failure.

Death of multiple myeloma cells induced by cAMP-signaling involves downregulation of Mcl-1 via the JAK/STAT pathway

There is a continuous search for new therapeutic targets for treatment of multiple myeloma (MM). Here we investigated the mechanisms involved in cAMP-induced apoptosis of human MM cells. cAMP-increasing agents rapidly inhibited activation of JAK1 and its substrate STAT3. In line with STAT3 being a regulator of Mcl-1 transcription, the expression of this pro-survival factor was rapidly and selectively reduced. Notably, exogenous interleukin-6 neither prevented the inhibition of JAK1/STAT3 nor the death of MM cells induced by cAMP. Our results suggest that cAMP-mediated killing of MM cells involves inhibition of the JAK/STAT pathway, making the cAMP-pathway a promising target for treatment of MM.

Influence of acidosis on cardiotonic effects of colforsin and epinephrine: a dose-response study

OBJECTIVE

Acidosis produces a negative inotropic effect on cardiac muscle against which catecholamines and phosphodiesterase III inhibitors have limited therapeutic effects. This study evaluated the effects of colforsin, which directly activates adenylate cyclase without β-adrenergic receptor activation, in isolated Langendorff rat hearts in a pH- and concentration-dependent manner.

DESIGN

Experimental animal study.

SETTING

A university laboratory.

PARTICIPANTS

Sprague-Dawley rats.

INTERVENTIONS

Hearts were isolated and perfused with 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid/Tyrode solution (pH 7.4) in the Langendorff preparation. The hearts were assigned randomly to the control (pH 7.4), mild acidosis (pH 7.0), or severe acidosis (pH 6.6) group (n = 8 per group) and were perfused continuously with colforsin 10(-7), 10(-6), and 10(-5) mol/L.

MEASUREMENTS AND MAIN RESULTS

Maximum dP/dt was determined, and the concentration-response relation was evaluated at each pH. Colforsin at 10(-6) mol/L increased the maximum dP/dt from 2,592 ± 557 to 5,189 ± 721 mmHg/s (p < 0.001) and from 1,942 ± 325 to 3,399 ± 608 mmHg/s (p < 0.001) in the control and mild acidosis groups, respectively; whereas colforsin, 10(-5) mol/L, significantly increased the maximum dP/dt even in the severe acidosis group. No significant difference was seen in maximum dP/dt among the 3 groups after infusion with colforsin 10(-5) mol/L.

CONCLUSIONS

In contrast to catecholamines and other inodilators, colforsin at a high concentration restores decreased cardiac contractility against severe acidosis to an extent similar to physiologic pH.

Capturing adenylyl cyclases as potential drug targets

Cyclic AMP (cAMP) is an important intracellular signalling mediator. It is generated in mammals by nine membrane-bound and one soluble adenylyl cyclases (ACs), each with distinct regulation and expression patterns. Although many drugs inhibit or stimulate AC activity through the respective upstream G-protein coupled receptors (for example, opioid or beta-adrenergic receptors), ACs themselves have not been major drug targets. Over the past decade studies on the physiological functions of the different mammalian AC isoforms as well as advances in the development of isoform-selective AC inhibitors and activators suggest that ACs could be useful drug targets. Here we discuss the therapeutic potential of isoform-selective compounds in various clinical settings, including neuropathic pain, neurodegenerative disorders, congestive heart failure, asthma and male contraception.

New signaling pathways associated with increased cardiac adenylyl cyclase 6 expression: implications for possible congestive heart failure therapy

Congestive heart failure (CHF) affects more than five million people in the United States and results in considerable morbidity, mortality, and economic costs. Patients with class III and IV CHF have a 40% to 50% probability of dying 5 years after symptom onset despite optimal therapy, a prognosis worse than many cancers. A variety of drugs and devices have improved survival-the 50% survival time in 1980 was just 18 months-but the outlook for patients remains dismal and the prevalence of CHF continues to increase. This unmet medical need underscores the importance of developing new approaches for the treatment of CHF. This brief review focuses on data from preclinical experiments regarding the effects of increased adenylyl cyclase type 6 (AC6) expression on cellular and cardiac function, and possible mechanisms for the unexpected favorable effects of increased AC6 content on the failing heart.

ReSETting PP2A tumour suppressor activity in blast crisis and imatinib-resistant chronic myelogenous leukaemia

The deregulated kinase activity of p210-BCR/ABL oncoproteins, hallmark of chronic myelogenous leukaemia (CML), induces and sustains the leukaemic phenotype, and contributes to disease progression. Imatinib mesylate, a BCR/ABL kinase inhibitor, is effective in most of chronic phase CML patients. However, a significant percentage of CML patients develop resistance to imatinib and/or still progresses to blast crisis, a disease stage that is often refractory to imatinib therapy. Furthermore, there is compelling evidence indicating that the CML leukaemia stem cell is also resistant to imatinib. Thus, there is still a need for new drugs that, if combined with imatinib, will decrease the rate of relapse, fully overcome imatinib resistance and prevent blastic transformation of CML. We recently reported that the activity of the tumour suppressor protein phosphatase 2A (PP2A) is markedly inhibited in blast crisis CML patient cells and that molecular or pharmacologic re-activation of PP2A phosphatase led to growth suppression, enhanced apoptosis, impaired clonogenic potential and decreased in vivo leukaemogenesis of imatinib-sensitive and -resistant (T315I included) CML-BC patient cells and/or BCR/ABL⁺ myeloid progenitor cell lines. Thus, the combination of PP2A phosphatase-activating and BCR/ABL kinase-inhibiting drugs may represent a powerful therapeutic strategy for blast crisis CML patients.

cAMP stimulates the secretory and proliferative capacity of the rat intrahepatic biliary epithelium through changes in the PKA/Src/MEK/ERK1/2 pathway

BACKGROUND/AIMS

To evaluate if increased cholangiocyte cAMP levels alone are sufficient to enhance cholangiocyte proliferation and secretion.

METHODS

Normal rats were treated in vivo with forskolin for two weeks. Cholangiocyte apoptosis, proliferation and secretion were evaluated. Purified cholangiocytes from normal rats were treated in vitro with forskolin in the absence or presence of Rp-cAMPs (a PKA inhibitor), PP2 (an Src inhibitor) or PD98059 (a MEK inhibitor). Subsequently, we evaluated cholangiocyte proliferation by determination of proliferating cellular nuclear antigen (PCNA) protein expression by immunoblots. We evaluated if the effects of forskolin on cholangiocyte functions are associated with changes in the cAMP/PKA/Src/MEK/ERK1/2 pathway.

RESULTS

Chronic administration of forskolin to normal rats increased the number of ducts, cAMP levels, and secretin-induced choleresis compared to controls. Forskolin-induced increases in cholangiocyte proliferation and secretion were devoid of cholangiocyte necrosis, inflammation and apoptosis. In vitro, in pure isolated cholangiocytes, forskolin increased cholangiocyte proliferation, which was ablated by Rp-cAMPs, PP2 and PD98059. The effects of forskolin on cholangiocyte proliferation were associated with increased activity of PKA, Src Tyrosine 139 (Tyr 139) and ERK1/2.

CONCLUSIONS

Modulation of the PKA/Src/MEK/ERK1/2 pathway may be important in the regulation of cholangiocyte growth and secretion observed in cholestatic liver diseases.