Compositions and methods for AL amyloid detection and uses thereof

1. A method of detecting light chain (LC) amyloid comprising:

(i) receiving a biological sample from a subject;

(ii) providing an imaging agent comprising a nanoparticle and anorganic heterocyclic molecule of the formula

or a pharmaceutically acceptable salt, solvate or polymorph thereof, including all tautomers and stereoisomers thereof, wherein n=3 or 4,

wherein,

is a bond connecting the organic heterocyclic molecule to the rest of the imaging agent:

the imaging agent is capable of specific LC amyloid or LC aggregate binding having a Kd of about 600 pM or less;

(iii) contacting the nanoparticle to the biological sample or LC amyloid isolated or amplified from the biological sample; and

(iv) detecting a binding value of the nanoparticle to an LC amyloid.

2. The method of claim 1 comprising amplifying the LC amyloid comprising:

(A) performing or having performed isolating light chain (LC) aggregates from the biological sample, resulting in isolates; incubating the isolates in a fibrillation buffer; providing rare AL amyloid particles to seed the amplification; creating a seed by amyloid fragmentation; and catalyzing amyloid formation; or

(B) performing or having performed providing a fixed amount of recombinantly expressed monomeric LC; adding the fixed amount of recombinantly expressed monomeric LC as a substrate to seed from the biological sample; and amplifying the monomeric LC, resulting in amyloid; and

(ii) performing or having performed quantifying LC amyloid by determining lag time (t lag ) from the imaging agent fluorescence amplitude and comparing to a reference.

3. The method of claim 1 , further comprising depleting albumin in the biological sample.

4. The method of claim 1 , wherein the LC aggregates comprise rigid unbranched aggregates of fibrils and the fibrils consist of proteins arranged in anti-parallel, cross β-pleated sheet configuration comprising strands perpendicular to a filament long axis.

5. The method of claim 1 , wherein the LC amyloid is detected in bone marrow, a kidney, a heart, a liver, a spleen, peripheral nerves, skin, a GI tract, serum, urine, urinary tract, tracheobronchial tree, conjunctiva, or thyroid.

6. The method of claim 1 , wherein

κ and λ soluble free LC (sFLCs) concentrations are measured;

a higher concentration, compared to a standard or control, of soluble free light chains (sFLCs) in the biological sample indicates that the subject has amyloidosis or renal failure;

the subject is treated for multiple myeloma (MM) with amyloidosis if FLCs concentration is higher than a standard or control; or

the subject is treated for MM without amyloidosis if FLCs concentration is not higher than a standard or control.

7. The method of claim 1 , further comprising stratifying the subject for AL MM therapeutic intervention or non-AL MM therapeutic intervention.

8. The method of claim 1 , wherein the biological sample is selected from one or more of: urine, blood, serum, saliva, plasma, biopsy sample, bone marrow aspirate, cardiac tissue, organ sample, and tissue sample.

9. The method of claim 1 , wherein the imaging agent further comprises a linker.

10. The method of claim 1 , wherein the organic heterocyclic molecule has high affinity for amyloid-based aggregates comprising beta-sheet structures, wherein the high affinity corresponds to (i) a Kd value less than about 600 pM to LC amyloid or (ii) a Kd of at most about 600 pM to LC amyloid.

11. The method of claim 1 , wherein the nanoparticle comprises Au, 199 Au, 198 Au, Cu, or 64 Cu.

12. The method of claim 9 , wherein the linker is a PEG or PEG derivative suitable for facilitating renal excretion and high-contrast imaging.

13. The method of claim 1 , wherein the imaging agent is capable of detecting λ light chains or κ light chains;

is a PET imaging agent comprising a radiolabel;

is a fluorescence imaging agent;

is detected using a fluorescence microplate reader; or

comprises a PET radionuclide into the nanoparticle.

14. The method of claim 1 , wherein the imaging agent is capable of binding AL light chains when the imaging agent is present at sub-nanomolar concentrations.

15. The method of claim 1 , wherein the imaging agent is water-soluble.

16. The method of claim 9 , wherein the imaging agent comprises Cu-NP-194 or Au-NP-194, wherein the linker is PEG, and the nanoparticle comprises 64 Cu, 199 Au, or 198 Au.

17. A method of detecting light chain (LC) amyloid comprising:

(i) receiving a biological sample from a subject;

(ii) providing an imaging agent comprising a nanoparticle and an organic heterocyclic molecule of the formula

 or a pharmaceutically acceptable salt, solvate or polymorph thereof, including all tautomers and stereoisomers thereof, wherein n=3 or 4,

wherein,

is a bond connecting the organic heterocyclic molecule to the rest of the imaging agent;

the imaging agent is capable of specific LC amyloid or LC aggregate binding having a Kd value of about 600 pM or less;

(iii) contacting the nanoparticle to the biological sample or LC amyloid isolated or amplified from the biological sample; and

(iv) detecting a binding value of the nanoparticle to an LC amyloid, wherein the LC aggregates comprise rigid unbranched aggregates of fibrils and the fibrils consist of proteins arranged in anti-parallel, cross β-pleated sheet configuration comprising strands perpendicular to a filament long axis.

18. A method of detecting light chain (LC) amyloid comprising:

(i) receiving a biological sample from a subject;

(ii) providing an imaging agent comprising a nanoparticle and an inorganic heterocyclic molecule of the formula

 or a pharmaceutically acceptable salt, solvate or polymorph thereof, including all tautomers and stereoisomers thereof, wherein n=3 or 4,

wherein,

is a bond connecting the organic heterocyclic molecule to the rest of the imaging agent;

the imaging agent is capable of specific LC amyloid or LC aggregate binding having a Kd value of about 600 pM or less;

(iii) contacting the nanoparticle to the biological sample or LC amyloid isolated or amplified from the biological sample; and

(iv) detecting a binding value of the nanoparticle to an LC amyloid, wherein the LC amyloid is detected in bone marrow, a kidney, a heart, a liver, a spleen, peripheral nerves, skin, a GI tract, serum, urine, urinary tract, tracheobronchial tree, conjunctiva, or thyroid.