α-Klotho Expression in Human Tissues.
BACKGROUND
α-Klotho has emerged as a powerful regulator of the aging process. To date, the expression profile of α-Klotho in human tissues is unknown, and its existence in some human tissue types is subject to much controversy.


OBJECTIVE
This is the first study to characterize systemwide tissue expression of transmembrane α-Klotho in humans. We have employed next-generation targeted proteomic analysis using parallel reaction monitoring in parallel with conventional antibody-based methods to determine the expression and spatial distribution of human α-Klotho expression in health.


RESULTS
The distribution of α-Klotho in human tissues from various organ systems, including arterial, epithelial, endocrine, reproductive, and neuronal tissues, was first identified by immunohistochemistry. Kidney tissues showed strong α-Klotho expression, whereas liver did not reveal a detectable signal. These results were next confirmed by Western blotting of both whole tissues and primary cells. To validate our antibody-based results, α-Klotho-expressing tissues were subjected to parallel reaction monitoring mass spectrometry (data deposited at ProteomeXchange, PXD002775) identifying peptides specific for the full-length, transmembrane α-Klotho isoform.


CONCLUSIONS
The data presented confirm α-Klotho expression in the kidney tubule and in the artery and provide evidence of α-Klotho expression across organ systems and cell types that has not previously been described in humans.
Renal Division (K.L., T.L., L.-L.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115; Cambridge Centre for Proteomics (A.G., K.S.L., T.F.H.), and School of Clinical Medicine (I.B.W., T.F.H.), University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Department of Pathology (D.S., S.J., S.T.), University Hospitals Coventry and Warwickshire, NHS Trust, Coventry CV2 2DX, United Kingdom; and Division of Translational Research (G.M., D.Z.), Warwick Medical School, University of Warwick, Coventry CV2 2DX, United Kingdom.
Kenneth
K
Lim
Renal Division (K.L., T.L., L.-L.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115; Cambridge Centre for Proteomics (A.G., K.S.L., T.F.H.), and School of Clinical Medicine (I.B.W., T.F.H.), University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Department of Pathology (D.S., S.J., S.T.), University Hospitals Coventry and Warwickshire, NHS Trust, Coventry CV2 2DX, United Kingdom; and Division of Translational Research (G.M., D.Z.), Warwick Medical School, University of Warwick, Coventry CV2 2DX, United Kingdom.
Arnoud
A
Groen
Renal Division (K.L., T.L., L.-L.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115; Cambridge Centre for Proteomics (A.G., K.S.L., T.F.H.), and School of Clinical Medicine (I.B.W., T.F.H.), University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Department of Pathology (D.S., S.J., S.T.), University Hospitals Coventry and Warwickshire, NHS Trust, Coventry CV2 2DX, United Kingdom; and Division of Translational Research (G.M., D.Z.), Warwick Medical School, University of Warwick, Coventry CV2 2DX, United Kingdom.
Guerman
G
Molostvov
Renal Division (K.L., T.L., L.-L.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115; Cambridge Centre for Proteomics (A.G., K.S.L., T.F.H.), and School of Clinical Medicine (I.B.W., T.F.H.), University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Department of Pathology (D.S., S.J., S.T.), University Hospitals Coventry and Warwickshire, NHS Trust, Coventry CV2 2DX, United Kingdom; and Division of Translational Research (G.M., D.Z.), Warwick Medical School, University of Warwick, Coventry CV2 2DX, United Kingdom.
Tzongshi
T
Lu
Renal Division (K.L., T.L., L.-L.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115; Cambridge Centre for Proteomics (A.G., K.S.L., T.F.H.), and School of Clinical Medicine (I.B.W., T.F.H.), University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Department of Pathology (D.S., S.J., S.T.), University Hospitals Coventry and Warwickshire, NHS Trust, Coventry CV2 2DX, United Kingdom; and Division of Translational Research (G.M., D.Z.), Warwick Medical School, University of Warwick, Coventry CV2 2DX, United Kingdom.
Kathryn S
KS
Lilley
Renal Division (K.L., T.L., L.-L.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115; Cambridge Centre for Proteomics (A.G., K.S.L., T.F.H.), and School of Clinical Medicine (I.B.W., T.F.H.), University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Department of Pathology (D.S., S.J., S.T.), University Hospitals Coventry and Warwickshire, NHS Trust, Coventry CV2 2DX, United Kingdom; and Division of Translational Research (G.M., D.Z.), Warwick Medical School, University of Warwick, Coventry CV2 2DX, United Kingdom.
David
D
Snead
Renal Division (K.L., T.L., L.-L.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115; Cambridge Centre for Proteomics (A.G., K.S.L., T.F.H.), and School of Clinical Medicine (I.B.W., T.F.H.), University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Department of Pathology (D.S., S.J., S.T.), University Hospitals Coventry and Warwickshire, NHS Trust, Coventry CV2 2DX, United Kingdom; and Division of Translational Research (G.M., D.Z.), Warwick Medical School, University of Warwick, Coventry CV2 2DX, United Kingdom.
Sean
S
James
Renal Division (K.L., T.L., L.-L.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115; Cambridge Centre for Proteomics (A.G., K.S.L., T.F.H.), and School of Clinical Medicine (I.B.W., T.F.H.), University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Department of Pathology (D.S., S.J., S.T.), University Hospitals Coventry and Warwickshire, NHS Trust, Coventry CV2 2DX, United Kingdom; and Division of Translational Research (G.M., D.Z.), Warwick Medical School, University of Warwick, Coventry CV2 2DX, United Kingdom.
Ian B
IB
Wilkinson
Renal Division (K.L., T.L., L.-L.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115; Cambridge Centre for Proteomics (A.G., K.S.L., T.F.H.), and School of Clinical Medicine (I.B.W., T.F.H.), University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Department of Pathology (D.S., S.J., S.T.), University Hospitals Coventry and Warwickshire, NHS Trust, Coventry CV2 2DX, United Kingdom; and Division of Translational Research (G.M., D.Z.), Warwick Medical School, University of Warwick, Coventry CV2 2DX, United Kingdom.
Stephen
S
Ting
Renal Division (K.L., T.L., L.-L.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115; Cambridge Centre for Proteomics (A.G., K.S.L., T.F.H.), and School of Clinical Medicine (I.B.W., T.F.H.), University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Department of Pathology (D.S., S.J., S.T.), University Hospitals Coventry and Warwickshire, NHS Trust, Coventry CV2 2DX, United Kingdom; and Division of Translational Research (G.M., D.Z.), Warwick Medical School, University of Warwick, Coventry CV2 2DX, United Kingdom.
Li-Li
LL
Hsiao
Renal Division (K.L., T.L., L.-L.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115; Cambridge Centre for Proteomics (A.G., K.S.L., T.F.H.), and School of Clinical Medicine (I.B.W., T.F.H.), University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Department of Pathology (D.S., S.J., S.T.), University Hospitals Coventry and Warwickshire, NHS Trust, Coventry CV2 2DX, United Kingdom; and Division of Translational Research (G.M., D.Z.), Warwick Medical School, University of Warwick, Coventry CV2 2DX, United Kingdom.
Thomas F
TF
Hiemstra
Renal Division (K.L., T.L., L.-L.H.), Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115; Cambridge Centre for Proteomics (A.G., K.S.L., T.F.H.), and School of Clinical Medicine (I.B.W., T.F.H.), University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Department of Pathology (D.S., S.J., S.T.), University Hospitals Coventry and Warwickshire, NHS Trust, Coventry CV2 2DX, United Kingdom; and Division of Translational Research (G.M., D.Z.), Warwick Medical School, University of Warwick, Coventry CV2 2DX, United Kingdom.
Daniel
D
Zehnder
D001011:Aorta / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism; D005966:Glucuronidase / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D000090265:Klotho Proteins; D009474:Neurons / Q000378:metabolism; D040901:Proteomics
D005966:Glucuronidase; D000090265:Klotho Proteins