Diagnostic use of cell free dna chromatin immunoprecipitation

Abstract

Methods of determining the origin of cell free DNA (cfDNA), for detecting death of a cell type or tissue in a subject, for determining a cellular state of a cell as it died, and combinations thereof, are provided. As are computer program products for doing same.

1 . A method of preparing cell free DNA (cfDNA) for analysis, the method comprising:
 a. providing a bodily fluid sample, wherein said sample comprises cfDNA;   b. contacting said sample with an antibody immobilized on a physical support, wherein said antibody binds to a DNA-associated protein;   c. isolating said physical support and any thereto bound DNA-associated proteins and cfDNA; and   d. ligating a DNA adapter to said cfDNA bound to said protein and physical support;   thereby preparing cfDNA for analysis.   
     
     
         2 . The method of  claim 1 , wherein said bodily fluid is selected from whole blood and plasma. 
     
     
         3 . The method of  claim 1 , wherein said antibody is covalently immobilized to said physical support. 
     
     
         4 . The method of  claim 1 , wherein said physical support is a bead. 
     
     
         5 . The method of  claim 1 , wherein said DNA associated protein is selected from a histone, a modified histone and a histone variant. 
     
     
         6 . The method of  claim 5 , wherein said modified histone is selected from Histone 3 monomethylated lysine 4 (H3K4me1), Histone 3 demethylated lysine 4 (H3K4me2), Histone 3 trimethylated lysine 36 (H3K36me3) and Histone 3 trimethylated lysine 4 (H3K4me3), optionally wherein said reagent is an anti-modified histone antibody or fragment thereof. 
     
     
         7 . The method of  claim 1 , further comprising eluting cfDNA ligated to a DNA adapter from said beads. 
     
     
         8 . The method of  claim 7 , further comprising sequencing said eluted cfDNA. 
     
     
         9 . The method of  claim 8 , further comprising designating a cfDNA molecule comprising a DNA sequence of an informative genomic location as originating from a cell in a cellular state, originating from a tissue, originating from a cell type or a combination thereof, wherein association of said DNA-associated protein with said informative genomic location is indicative of said cellular state, tissue of origin, cell type or combination thereof in the cell that released said cfDNA and wherein said method is a method of determining a cellular state, tissue of origin cell type or combination thereof of a cell that released its DNA. 
     
     
         10 . The method of  claim 9 , wherein said cell that released its DNA is a dead cell and the method is for detecting death of at least one of:
 a. a cell type in a subject,   b. a tissue in a subject, and   c. a cell in a cellular state in a subject.   
     
     
         11 . The method of  claim 9 , wherein said cellular state is a disease state, optionally wherein said disease state is selected from bacteremia, cancer, pre-cancer, infection, neurodegenerative disease, tissue damage, cardiac disease or damage, brain disease or damage, gastrointestinal disease or damage, liver disease, inflammation, autoimmune disease, arthritis, liver disease, damage or inflammation, bowel inflammation, autoimmune disease, tissue damage from drug side effects, tissue necrosis, and diabetes. 
     
     
         12 . The method of  claim 9 , wherein at least one of:
 a. association of said DNA-associated protein with said genomic location is indicative of active transcription and said genomic location is within a tissue, cell type or cellular state specific gene or enhancer element or is at a disease-specific mutation;   b. wherein said DNA-associated protein is a marker of active transcription and said designating comprises comparing said sequenced cfDNA to a known transcriptional program of a tissue, cell type or cellular state, wherein a cfDNA with a sequence that is from a gene transcribed in said transcriptional program is from said tissue, cell type or cellular state; and   c. wherein association of said DNA-associated protein with said genomic location is indicative of silenced transcription and said genomic location is within a repressor element, or a gene silenced in said tissue, cell-type or cellular state, or is at a disease-specific mutation.   
     
     
         13 . The method of  claim 8 , wherein said sequencing is Next Generation Sequencing, High Throughput Sequencing or Massively Parallel Sequencing. 
     
     
         14 . The method of  claim 7 , wherein said adapter is a sequencing adapter. 
     
     
         15 . The method of  claim 14 , wherein said sequencing adapter is a barcoded sequencing adapter. 
     
     
         16 . The method of  claim 9 , wherein said designating comprises at least one of:
 a. comparing said sequenced cfDNA to at least 10 genomic locations with the greatest unique association of said DNA-associated protein in a tissue, cell type or cellular state, and wherein a cfDNA with a sequence that is the same as a DNA sequence within said at least 10 genomic locations is considered to be from said tissue, cell type or cellular state;   b. comparing the sequenced cfDNA to a DNA-protein association atlas of at least 5 cell types or tissues, wherein said atlas comprises at least 10 genomic location with the greatest unique association of said DNA-associated protein in each of said 5 cell types or tissues, and wherein a cfDNA with a sequence that is the same as a DNA sequence within said at least 10 genomic locations is considered to be from said tissue or cell type; and   c. comparing the sequenced cfDNA to a transcriptional program atlas of at least 5 transcriptional programs, wherein said atlas comprises at least one genomic location with the greatest unique association of said DNA-associated protein in each of said 5 transcriptional programs and wherein a cfDNA with a sequence that is the same as a DNA sequence within said at least one genomic location indicates activation of said transcriptional program.   
     
     
         17 . The method of  claim 9 , wherein said cellular state is selected from: hypoxia, inflammation, ER stress, mitochondrial stress, interferon response, quiescence, senescence, cycling, malignant, and calcium flux. 
     
     
         18 . The method of  claim 9 , wherein said informative genomic location is selected from a promoter, an enhancer element, a silencer element, a gene body and a disease-associated mutation. 
     
     
         19 . The method of  claim 9 , wherein said cellular state is selected from: hypoxia, inflammation, ER stress, mitochondrial stress, interferon response, quiescence, senescence, cycling, malignant, and calcium flux. 
     
     
         20 . The method of  claim 9 , wherein said sample is from a subject and said method is a method of detecting and treating a disease in said subject and further comprises treating said subject with a suitable treatment based on the cellular state, tissue of origin, cell type or a combination thereof of said cell that died in said subject.