Fasudil (

INN Inns are generally establishments or buildings where travelers can seek lodging, and usually, food and drink. Inns are typically located in the country or along a highway. Before the advent of motorized transportation, they also provided accomm ...

) is a potent Rho-kinase inhibitor and

vasodilator Vasodilation, also known as vasorelaxation, is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. Blood vessel wal ...

. Since it was discovered, it has been used for the treatment of

cerebral vasospasm Cerebral vasospasm is the prolonged, intense vasoconstriction of the larger conducting arteries in the subarachnoid space which is initially surrounded by a clot. Significant narrowing of the blood vessels in the brain develops gradually over the ...

, which is often due to

subarachnoid hemorrhage Subarachnoid hemorrhage (SAH) is bleeding into the subarachnoid space—the area between the arachnoid (brain), arachnoid membrane and the pia mater surrounding the human brain, brain. Symptoms may include a thunderclap headache, severe heada ...

, as well as to improve the cognitive decline seen in

stroke Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...

patients. It has been found to be effective for the treatment of

pulmonary hypertension Pulmonary hypertension (PH or PHTN) is a condition of increased blood pressure in the pulmonary artery, arteries of the lungs. Symptoms include dypsnea, shortness of breath, Syncope (medicine), fainting, tiredness, chest pain, pedal edema, swell ...

. It has been demonstrated that fasudil could improve

memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembe ...

in normal mice, identifying the drug as a possible treatment for age-related or

neurodegenerative A neurodegenerative disease is caused by the progressive loss of neurons, in the process known as neurodegeneration. Neuronal damage may also ultimately result in their death. Neurodegenerative diseases include amyotrophic lateral sclerosis, mul ...

memory loss. It has been approved for use in Japan and China since 1995, but has not been approved by the

United States Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...

or by the

European Medicines Agency The European Medicines Agency (EMA) is an agency of the European Union (EU) in charge of the evaluation and supervision of pharmaceutical products. Prior to 2004, it was known as the European Agency for the Evaluation of Medicinal Products ...

. Woolsey Pharmaceuticals is developing BRAVYL (oral fasudil) for various neurodegenerative diseases.

Molecular mechanism

Fasudil (HA-1077) is a selective RhoA/

Rho kinase Rho-associated protein kinase or Rho-associated coiled-coil kinase (ROCK) is a kinase belonging to the AGC (PKA/ PKG/PKC) family of serine-threonine specific protein kinases. It is involved mainly in regulating the shape and movement of cells by ...

(ROCK) inhibitor. ROCK is an enzyme that plays an important role in mediating vasoconstriction and vascular remodeling in the pathogenesis of pulmonary hypertension. ROCK induces vasoconstriction by phosphorylating the myosin-binding subunit of myosin light chain (MLC) phosphatase, thus decreasing MLC phosphatase activity and enhancing vascular smooth muscle contraction.

ACE expression

Angiotensin-converting enzyme Angiotensin-converting enzyme (), or ACE, is a central component of the renin–angiotensin system (RAS), which controls blood pressure by regulating the volume of fluids in the body. It converts the hormone angiotensin I to the active vasocon ...

(ACE) is an enzyme that catalyzes the conversion of angiotensin-I (Ang-I) to angiotensin-II (Ang-II). Ang-II is a peptide hormone which increases blood pressure by initiating

vasoconstriction Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vesse ...

and

aldosterone Aldosterone is the main mineralocorticoid steroid hormone produced by the zona glomerulosa of the adrenal cortex in the adrenal gland. It is essential for sodium conservation in the kidney, salivary glands, sweat glands, and colon. It plays ...

secretion. ROCK increases ACE expression and activity in pulmonary hypertension. By inhibiting ROCK with fasudil, circulating ACE and Ang-II are reduced, leading to a decrease in pulmonary vascular pressure.

eNOS expression

Endothelial nitric oxide synthase (eNOS) mediates the production of the vasodilator

nitric oxide Nitric oxide (nitrogen oxide, nitrogen monooxide, or nitrogen monoxide) is a colorless gas with the formula . It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes den ...

(NO). Pulmonary arterial cell cultures treated with fasudil showed a significant increase in eNOS mRNA levels in a dose dependent manner, and the half-life of eNOS mRNA increased 2-folds. These findings suggested that ROCK inhibition with fasudil increases eNOS expression by stabilizing eNOS mRNA, which contributed to an increase of NO level to enhance vasodilation.

ERK activation

The proliferative effects of ROCK on vascular endothelial cells is due to the activation of extracellular signal-regulated kinase (ERK). ERK mediates cell proliferation via the phosphorylation of p27Kip1, thus accelerating the degradation rate of

p27Kip1 Cyclin-dependent kinase inhibitor 1B (p27Kip1) is an enzyme inhibitor that in humans is encoded by the CDKN1B gene. It encodes a protein which belongs to the ''Cip/Kip'' family of cyclin dependent kinase (Cdk) inhibitor proteins. The encoded pr ...

. p27Kip1 is a cyclin-dependent kinase (CDK) inhibitor which down-regulates cell cycle by binding cyclin-CDK complex. Human pulmonary arterial smooth muscle cells treated with fasudil showed a decrease in cell proliferation in a dose-dependent manner. Fasudil also decreases ERK activities, as well as increases level of p27Kip1. This suggested that the anti-proliferative effects of fasudil is due to the decrease of ERK activities via the inhibition of ROCK.

Direct inhibition of α-synuclein aggregation

In addition to ROCK inhibition, fasudil has also been demonstrated to directly modulate the aggregation of

α-synuclein Alpha-synuclein (aSyn) is a protein that in humans is encoded by the ''SNCA'' gene. It is a neuronal protein involved in the regulation of synaptic vesicle trafficking and the release of neurotransmitters. Alpha-synuclein is abundant in the bra ...

, both ''in vitro'' and in cellular models of neurodegenerative disease. Aggregation of α-synuclein is a major hallmark of

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease primarily of the central nervous system, affecting both motor system, motor and non-motor systems. Symptoms typically develop gradually and non-motor issues become ...

, and has also been observed in other neurodegenerative diseases. Physical interactions between α-synuclein and fasudil have been shown to take place with α-synuclein in the intrinsically disordered state, which places fasudil among a small number of drug-like molecules that directly interact with intrinsically disordered proteins.

References