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Potential new drug target

Posted: Tue Feb 19, 2008 9:16 am
by Frank
Brain drug target discovery in Multiple Sclerosis 18 February 2008
US researchers have found two potential targets for treating multiple sclerosis after an extensive trawl through proteins in the brain.

Comparison of 2,538 proteins from MS patients with those from healthy brains showed damage in two proteins not before linked to the disease.

In mice blocking the effects of the proteins led to reversal of symptoms, the study in Nature reported.

There are about 85,000 people with MS in the UK.

The condition is caused by a defect in the body's immune system, which turns in on itself, attacking the fatty myelin sheath which coats the nerves, leading to symptoms including blurred vision, loss of balance and, in some cases, paralysis.

Study leader Professor Lawrence Steinman said this was the first large-scale study to search for defective proteins in MS lesions in the brain.

They found a few proteins peculiar to MS brain lesions.

But two in particular - tissue factor and protein C inhibitor - showed signs of damage during the chronic active stage of the disease.

These normally participate in the control of blood clotting and in anti-inflammatory pathways. The researchers guessed that the damaged proteins might be helping the progression of MS and, by using inhibitors of the proteins found they could successfully ameliorate the disease in mice.

Treatment

Professor Steinman, from Stanford University School of Medicine in California, said the finding opened up the way for new treatments.

However, using existing drugs which interfere with the control of blood clotting would be dangerous because of an increased risk of bleeding.

Professor Neil Scolding, from the University of Bristol Institute of Clinical Neurosciences, said: "From the scientific perspective, the exciting thing is that it's pretty much the first time that proteomics has directly yielded a candidate molecule that is both unexpected and novel on the one hand and has therapeutic potential.

"From the clinical perspective, showing that treatment approaches predicted by this proteomic interrogation of MS tissue do have a clear impact in experimental models of MS is extremely promising.

"This points the way to a new area of MS research of considerable interest, and which could well lead in the future to new lines of treatment."

Dr Laura Bell, Research Communications Officer at the MS Society, said she looked forward to seeing how the research progressed.

"This is early research but provides an interesting insight into some of the potential players that cause different types of damage to the central nervous system in people with MS.

"Understanding how MS develops is vital to target therapies for the condition."

Source: BBC News © BBC 2008 (17/02/08)

Posted: Fri Jul 11, 2008 9:00 am
by gibbledygook
Here's the pubmed article:
1: Nature. 2008 Feb 28;451(7182):1076-81. Epub 2008 Feb 17. Links
Proteomic analysis of active multiple sclerosis lesions reveals therapeutic targets.Han MH, Hwang SI, Roy DB, Lundgren DH, Price JV, Ousman SS, Fernald GH, Gerlitz B, Robinson WH, Baranzini SE, Grinnell BW, Raine CS, Sobel RA, Han DK, Steinman L.
Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California 94305, USA.

Understanding the neuropathology of multiple sclerosis (MS) is essential for improved therapies. Therefore, identification of targets specific to pathological types of MS may have therapeutic benefits. Here we identify, by laser-capture microdissection and proteomics, proteins unique to three major types of MS lesions: acute plaque, chronic active plaque and chronic plaque. Comparative proteomic profiles identified tissue factor and protein C inhibitor within chronic active plaque samples, suggesting dysregulation of molecules associated with coagulation. In vivo administration of hirudin or recombinant activated protein C reduced disease severity in experimental autoimmune encephalomyelitis and suppressed Th1 and Th17 cytokines in astrocytes and immune cells. Administration of mutant forms of recombinant activated protein C showed that both its anticoagulant and its signalling functions were essential for optimal amelioration of experimental autoimmune encephalomyelitis. A proteomic approach illuminated potential therapeutic targets selective for specific pathological stages of MS and implicated participation of the coagulation cascade.
http://www.ncbi.nlm.nih.gov/pubmed/1827 ... d_RVDocSum

What's hirudin?
From wikipedia today:
Hirudin is a naturally occurring peptide in the salivary glands of medicinal leeches (such as Hirudo medicinalis) that has a blood anticoagulant property. This is fundamental for the leeches’ alimentary habit of hematophagy, since it keeps the blood flowing after the initial phlebotomy performed by the worm on the host’s skin.
In 1884, the British physiologist John Berry Haycraft discovered that the leech secreted a powerful anticoagulant, which he named hirudin, though it was not isolated until the 1950s, nor its structure fully determined until 1976. Full length, hirudin is made up of 65 amino acids. These amino acids are organised into a compact N-terminal domain containing three disulfide bonds and a C-terminal domain which is completely disordered, when the protein is un-complexed in solution.[1][2] Natural hirudin contains a mixture of various isoforms of the protein. However, recombinant techniques can be used to produce homogeneous preparations of hirudin.[3]A key event in the final stages of blood coagulation is the conversion of fibrinogen into fibrin by the serine protease enzyme thrombin.[4] Thrombin is produced from prothrombin, by the action of an enzyme, prothrombinase, in the final states of coagulation. Fibrin is then cross linked by factor XIII to form a blood clot. The principal inhibitor of thrombin in normal blood circulation is antithrombin III.[3] Similar to antithrombin III, the anticoagulatant activity of hirudin is based on its ability to inhibit the pro-coagulant activity of thrombin.

Hirudin is the most potent natural inhibitor of thrombin. Unlike antithrombin III hirudin binds to and inhibits only the activity of thrombin forms with a specific activity on fibrinogen.[3] Therefore, hirudin prevents or dissolves the formation of clots and thrombi (i.e. it has a thrombolytic activity), and has therapeutic value in blood coagulation disorders, in the treatment of skin hematomas and of superficial varicose veins, either as an injectable or a topical application cream. In some aspects, hirudin has advantages over more commonly used anticoagulants and thrombolytics, such as heparin, as it does not interfere with the biological activity of other serum proteins and can also act on complexed thrombin.

It is difficult to extract large amounts of hirudin from natural sources, so a method for producing and purifying this protein using recombinant biotechnology has been developed. This has led to the development and marketing of a number of hirudin based anticoagulant pharmaceutical products such as lepirudin (Refludan) and Desirudin (Revasc/Iprivask). Several other direct thrombin inhibitors are derived chemically from hirudin.
Maybe try Vitamin K:
from wikipedia:
Protein C is a major physiological anticoagulant. It is a vitamin K-dependent serine protease enzyme (EC 3.4.21.69) that is activated by thrombin into activated protein C (APC). The activated form (with protein S and phospholipid as a cofactor) degrades Factor Va and Factor VIIIa. It should not be confused with C peptide or c-reactive protein or protein kinase C.

The protein C pathway’s key enzyme, activated protein C, provides physiologic antithrombotic activity and exhibits both anti-inflammatory and anti-apoptotic activities. Its actions are related to development of thrombosis and ischemic stroke. The protein C pathway of the coagulation of the blood involves the influences of lipids and lipoproteins and the study of the strong epidemiologic association between hyperlipidemia and hypercoagulability.[
Or danshen:
1: Ann Pharmacother. 2001 Apr;35(4):501-4. Links
Interaction between warfarin and danshen (Salvia miltiorrhiza).Chan TY.
Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories. tykchan@cuhk.edu.hk

OBJECTIVE: To discuss the potential for an adverse interaction between the Chinese herb danshen, the dry root and rhizome of Salvia miltiorrhiza Bge, and warfarin. DATA SOURCES: A MEDLINE search was performed (from January 1966 through October 2000) using the key words danshen and Salvia miltiorrhiza. All articles written in English or with an English extract were considered for review. STUDY SELECTION AND DATA EXTRACTION: All studies of antithrombotic effects of danshen or interaction between danshen and warfarin were evaluated. Previous case reports of an adverse interaction between danshen and warfarin were reviewed. DATA SYNTHESIS: Danshen is commonly used in mainland China for the treatment of atherosclerosis-related disorders such as cardiovascular and cerebrovascular diseases. Danshen can affect hemostasis in several ways, including inhibition of platelet aggregation, interference with the extrinsic blood coagulation, antithrombin III-like activity, and promotion of fibrinolytic activity. Single-dose and steady-state studies in rats indicated that danshen increased the absorption rate constants, AUCs, maximum concentrations, and elimination half-lives, but decreased the clearances and apparent volume of distribution of both R- and S-warfarin. Consequently, the anticoagulant response to warfarin was exaggerated. Three cases have previously been published reporting gross overanticoagulation and bleeding complications when patients receiving chronic warfarin therapy also took danshen. CONCLUSIONS: Because of both pharmacokinetic and pharmacodynamic interactions, danshen should be avoided in patients taking warfarin.

PMID: 11302416 [PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov/pubmed/1130 ... d_RVDocSum

Posted: Fri Jul 11, 2008 1:10 pm
by gwa
When the original article about Dr Steinman's protein research was posted earlier this year, I was pleased to read that he intends to follow through with this discovery.

He indicated that he would open his own company to continue the research if he could not find an already established firm willing to work with him. At least he is not going to just give his discovery to a big pharma company and watch then shelve it for decades.

gwa

Posted: Sat Jul 12, 2008 3:36 am
by gibbledygook
The other promising thing about his research that it might only involve fairly innocuous medication to alleviate the hypercoagulation which is, after all, a fairly common problem. I have ordered some salvia miltiorrhiza from a us herbal company and will comment on any changes in my regimen section. 8)