Therapeutic Target Database (TTD) is a pharmaceutical and medical repository
constructed by the Innovative Drug Research and Bioinformatics Group (IDRB) at
Zhejiang University, China and the Bioinformatics and Drug Design Group at the
National University of Singapore
The National University of Singapore (NUS) is a national university, national Public university, public research university in Singapore. It was officially established in 1980 by the merging of the University of Singapore and Nanyang University ...
. It provides information about known and explored therapeutic
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
and
nucleic acid
Nucleic acids are large biomolecules that are crucial in all cells and viruses. They are composed of nucleotides, which are the monomer components: a pentose, 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nuclei ...
targets,
the targeted disease,
pathway information
and the corresponding drugs directed at each of these targets.
Detailed knowledge about target function, sequence, 3D structure, ligand binding properties,
enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
nomenclature and drug structure, therapeutic class, and clinical development status.
TTD is freely accessible without any login requirement at https://idrblab.org/ttd/.
Statistics
This database contains 3,730 therapeutic targets (532 successful, 1,442 clinical trial, 239 preclincial/patented and 1,517 research targets) and 39,862 drugs (2,895 approved, 11,796 clinical trial, 5,041 preclincial/patented and 20,130 experimental drugs). The targets and drugs in TTD cover 583 protein biochemical classes and 958 drug therapeutic classes, respectively.
The latest version of the International Classification of Diseases (ICD-11) codes released by WHO are incorporated in TTD to facilitate the clear definition of disease/disease class.
Validation of Primary Therapeutic Target
Target validation normally requires the determination that the target is expressed in the disease-relevant cells/tissues,
it can be directly modulated by a drug or drug-like molecule with adequate potency in biochemical assay,
and that target modulation in cell and/or animal models ameliorates the relevant disease phenotype.
Therefore, TTD collects three types of target validation data:
* Experimentally determined potency of drugs against their primary target or targets.
* Evident potency or effects of drugs against disease models (cell-lines, ex-vivo, in-vivo models) linked to their primary target or targets.
* Observed effects of target knockout, knockdown, RNA interference, transgenetic, antibody or antisense treated in-vivo models.
Categorization of Therapeutic Targets based on Clinical Status
The therapeutic targets in TTD are categorized into successful target, clinical trial target, preclinical target, patented target, and literature-reported target, which are defined by the highest status of their corresponding drugs.
* Successful target: targeted by at least one approved drug;
* Clinical trial target: not targeted by any approved drug, but targeted by at least one clinical trial drug;
* Preclinical target: not targeted by any approved/clinical trial drug, but targeted by at least one preclinical drug;
* Patented target: not targeted by any approved/clinical trial/preclinical drug, but targeted by at least one patented drug;
* Literature-reported target: targeted by investigative drugs only.
Classification of Therapeutic Targets based on Molecular Types
The molecular types of therapeutic targets in TTD include protein, nucleic acid, and other molecule.
*
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
: the most common type of target in drug development
*
Nucleic acid
Nucleic acids are large biomolecules that are crucial in all cells and viruses. They are composed of nucleotides, which are the monomer components: a pentose, 5-carbon sugar, a phosphate group and a nitrogenous base. The two main classes of nuclei ...
: include DNA, mRNA, miRNA, lncRNA targets
* Other molecule: such as uric acid, iron, and reactive oxygen species
Different Types of Drugs Collected in TTD
The main drug types in TTD include small molecule, antibody, nucleic acid drug, cell therapy, gene therapy and vaccine.
*
Small molecule
In molecular biology and pharmacology, a small molecule or micromolecule is a low molecular weight (≤ 1000 daltons) organic compound that may regulate a biological process, with a size on the order of 1 nm. Many drugs are small molecules; ...
: the most common medications in the pharmaceutical market
*
Antibody
An antibody (Ab) or immunoglobulin (Ig) is a large, Y-shaped protein belonging to the immunoglobulin superfamily which is used by the immune system to identify and neutralize antigens such as pathogenic bacteria, bacteria and viruses, includin ...
: includes monoclonal antibodies and several alternatives such as antibody-drug conjugates, bispecific antibodies, IgG mixtures, and antibody fusion proteins
* Nucleic acid drug: mainly include antisense oligonucleotides, small interfering RNAs, small activating RNA, microRNAs, mRNAs and so on
*
Cell therapy: inject, graft or implant viable cells into a patient in to effectuate a medicinal effect
*
Gene therapy
Gene therapy is Health technology, medical technology that aims to produce a therapeutic effect through the manipulation of gene expression or through altering the biological properties of living cells.
The first attempt at modifying human DNA ...
: manipulate gene expression or alter the biological properties of living cells to produce the therapeutic effect
*
Vaccine
A vaccine is a biological Dosage form, preparation that provides active acquired immunity to a particular infectious disease, infectious or cancer, malignant disease. The safety and effectiveness of vaccines has been widely studied and verifi ...
: provide active acquired immunity to a particular infectious or malignant disease
Main Advancement in Different Versions of TTD
2024 Update (''Nucleic Acids Res''. 2023, doi: 10.1093/nar/gkad751)
■ Target druggability illustrated by molecular interactions or regulations;
■ Target druggability characterized by different human system features;
■ Target druggability reflected by diverse cell-based expression variations;
2022 Update (''Nucleic Acids Res''. 2022, 50: D1398-D1407)
■ Structure-based activity landscape and drug-like property profile of targets;
■ Prodrugs together with their parent drug and target;
■ Co-targets modulated by approved/clinical trial drugs;
■ Poor binders and non-binders of targets;
2020 Update (''Nucleic Acids Res''. 2020, 48: D1031-D1041)
■ Target regulators (microRNAs & transcription factors) and target-interacting proteins;
■ Patented agents and their targets (structures and experimental activity values if available);
2018 Update (''Nucleic Acids Res''. 2018, 46: D1121-D1127)
■ Differential expression profiles and downloadable data of targets in patients and healthy individuals;
■ Target combination of multitarget drugs and combination therapies;
2016 Update (''Nucleic Acids Res''. 2016, 44: D1069-D1074)
■ Cross-links of most TTD target and drug entries to the corresponding pathway entries;
■ Access of the multiple targets and drugs cross-linked to each of these pathway entries;
2014 Update (''Nucleic Acids Res''. 2014, 42: D1118-D1123)
■ Biomarkers for disease conditions;
■ Drug scaffolds for drugs/leads;
2012 Update (''Nucleic Acids Res''. 2012, 40: D1128-D1136)
■ Target validation information (drug-target-disease);
■ Quantitative structure activity relationship models (QSAR) for compounds;
2010 Update (''Nucleic Acids Res''. 2010, 38: D787-D791)
■ Clinical trial drugs and their targets;
■ Similarity target and drug search.
References
{{Reflist
External links
Therapeutic Target Database home pageArticle on PubMedInnovative Drug Research and Bioinformatics Group
Proteins
Pharmacology literature
Chemical databases
Medical databases
Drugs in Singapore
de:Target (Biologie)
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