What Is a Proteome?
The proteome is the entire set of proteins expressed in the form of a genome, tissue, cell, or organism under certain conditions at a given time. The study of the proteome is known as “ proteomics.”
What Is a Human Ureter Proteome?
Several diseases can be diagnosed by detecting alterations in the composition of urine, including various proteins and polypeptides. Urine is regarded as an essential biofluid in proteomics. It is used in proteomics because of its stability and noninvasive nature. Most of the proteins found in the urine usually originate from the urogenital tract. However, the exact source of these proteins in the urinary tract is difficult to determine. The specific part of the urogenital tract, like the kidneys, ureter, or urinary bladder, is still not specified.
The human urinary proteome is screened for disease biomarkers. It is preferred over other biofluids like plasma and serum because of its relative simplicity and stability, particularly for the identification of protein or peptide biomarkers. Urine is produced by the kidneys and carried by the ureters, 25 to 30 cm tubes in length, and stored in the urinary bladder. In this process, 90 percent of the urine is reabsorbed. The remaining 10 percent of urine consists of wasted molecules and some protein molecules found in the urogenital tract and plasma.
What Are Proteins Found in the Human Ureter?
A comprehensive study or analysis of the ureter proteome has been performed. This study concluded that out of 2217 nonredundant ureter proteins, 751 proteins, or 33.8 percent, were detected as urinary or polypeptide proteins. When ureter proteins not shown in this study were compared to urinary bladder and prostate human proteins, it was reported that 21 proteins are specifically present in the ureter tissue. This finding will further help in the identification of biomarkers associated with ureter diseases like ureter carcinoma. Human ureter proteomics further helps to provide important information to scientists working in the field of urine biomarker discovery and urology in general.
The urinary proteins may originate from the following:
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Secretions of soluble proteins in the renal tubules.
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Sloughed cells of the urogenital tract.
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Glomerular‐filtrate plasma proteins.
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Membranous or cytosolic exosomal proteins.
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Glycosylphosphatidylinositol‐anchored protein like uromodulin.
In a normal healthy individual, the urinary proteome that originates in the urogenital tract accounts for 70 percent. The remaining 30 percent are plasma proteins that originate in the glomerulus (a part of the kidney responsible for filtration and composed of a network of capillaries).
What Is the Potential Use of the Urinary Proteome?
The potential uses of the urinary proteome have been described in the following urogenital diseases:
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Acute transplant rejection.
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Chronic kidney disease.
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Cancer.
What Is Analyzed in the Ureter Proteome?
It was proposed that some of the proteins may be released in urine as it passes through the ureter as exosomes or as a shredded epithelium. To confirm this, the ureter proteome was compared with an exosomal urinary database, comprehensive mass spectrometric urinary database, and kidney database. Further, the retained proteins of the ureter were compared to prostate and urinary bladder databases from the human protein atlas (HPA).
A normal healthy sample of around four to five centimeters in length was dissected from a ureter of a diseased kidney. Protein extracts were identified by putting the dissected ureter tissues in a protein prefractionation buffer containing thiourea, urea, Dithiothreitol (DTT), glycerol, and buffer with ampholytes of pH three to ten. Further, Complete ultra proteases were added to the buffer, and for protein extraction, the Precellys 24 tissue homogenizer was employed at four degrees Celsius. Then the two milligrams of protein extract recovered were subjected to fractionation. The complete analysis reported 2217 non-redundant proteins present in the ureter protein. Moreover, ureter protein data were compared with urine, urinary exosome, and kidney databases. The result documented that 24.3 percent of the ureter proteins were found in the urine database reports in the past. The data also reported that 21 percent of ureter proteins were excreted as urinary exosomes. Confirming these proteins in urine helps in an accurate and supportive diagnosis of ureter diseases.
Conclusion:
To conclude, it was reported that over one‐third, or 33.8 percent of ureter proteomes, were found in urine as protein or polypeptides. The exact genesis of urinary proteins is still at its earliest stages. The complete picture of urine biomarkers can be illustrated when plasma proteins are also identified along with the signature proteins of the urogenital tract tissues.
