Kinji Matsuura

Does catalytic activity of bence-jones proteins contribute to the pathogenesis of multiple myeloma?

Some Bence-Jones proteins have been found to be capable of hydrolyzing DNA, chromogenic amide substrates, such as benzoylarginine p-nitroanilide, and natural oligopeptides, such as arginine vasopressin. Patients who excrete Bence-Jones protein with the DNA-nicking activity have shown moderately severe symptoms. When incubated with LLC-PK1 (porcine kidney proximal tu bule) cells, some Bence Jones proteins penetrated the cytoplasm, and en tered the nucleus with little or no degradation of epitopes. Intranuclear Bence Jones proteins sultimately induced DNA fragmentation in situ and cell death. This cytocidal activity was not directly associated with the DNA-nicking activity, since Bence Jones proteins with no detectable DNase activity also produced cell death. These results, however, suggest that the biological activities of Bence Jones proteins described here makes a significant contribution to the development and/or deterioration of multiple myeloma.

Pathogenicity of catalytic antibodies: catalytic activity of Bence Jones proteins from myeloma patients with renal impairment can elicit cytotoxic effects

Abstract Some Bence Jones proteins (BJPs) can display catalytic activity. Although the catalytic activity of BJPs might be associated with the pathogenesis of disease, this relationship has not yet been established. We tested the effects of seven BJPs on LLC-PK1 cells to assess their pathogenicity. Two out of the seven BJPs showed cytotoxic activity, as assessed by microscopic analysis, the WST method and TUNEL staining. Moreover, the cytotoxic BJPs were excreted by patients who presented with renal impairment. The cytotoxic BJPs displayed 20- to 40-fold higher catalytic activities (k cat of 3.5–2.2 min-1) in hydrolyzing a chromogenic substrate compared to the other BJPs. By treating the cytotoxic BJPs with diisopropylfluorophosphate, they lost not only their catalytic activity, but also the cytotoxic effects. These results indicate a direct link between cytotoxicity and the catalytic activity of the BJPs. The catalytic activity of BJPs contributes to the pathogenesis, as well as to development, of symptoms of multiple myeloma. Inhibition of the catalytic activity of BJPs may form the basis of a novel treatment for multiple myeloma patients with renal dysfunction.

Cloning and sequencing of cDNA encoding haptoglobin, an acute phase protein in Syrian hamster, Mesacricetus auratus.

One of the most prominent acute phase proteins in Syrian hamster (Mesacricetus auratus) was identified as haptoglobin and cDNA encoding this protein was sequenced. The deduced amino acid sequence of the mature protein is 83.6, 80.5, 79.6, and 76.1% identical to those of mouse, rat, human (1 s isoform), and dog homologues, respectively. As compared with six known members of this family, including human haptoglobin-related protein, hamster haptoglobin had 11 unique substitutions and one unique codon deletion, that is, the corresponding residues have been conserved in all other members. This indicates that hamster haptoglobin gene has accumulated these unique mutations after the time of cricetid-murid split while the ancestral sequence has been conserved in all other species examined. Hamster haptoglobin, however, contains nine cysteine residues, all of which are found in conserved positions in primate and rodent homologues. Molecular phylogenetic trees of alpha- and beta-chains show that the alpha-chain is more divergent than the beta-chain and that the difference in genetic distance between canine and hamster alpha-chains is much greater than that of corresponding beta-chains.

Amidase and peptidase activities of polyclonal immunoglobulin G present in the sera of patients with rheumatoid arthritis.

Polyclonal Immunoglobulin (Ig) G from patients with rheumatoid arthritis (RA) and healthy subjects hydrolyzed carbobenzoxy−Val−Gly−Arg p-nitroanilide and D−Pro−Phe−Arg p-nitroanilide. RA IgG exhibited higher activity against the former substrate, but not the latter. On the other hand, RA IgG showed reduced activity against D−Pro−Phe−Arg methylcoumarinamide, when compared with those of the healthy controls. These results suggest that RA IgGs differ from normal IgGs in the substrate specificity of amidase activity. Preliminary studies have shown that two out of three RA IgG samples cleaved a pentapeptide—Gln−Arg−Arg−Arg−Ala−Ala— which is assumed to be associated with the risk of developing RA (Gregersen, P. K. et al. (1987), Arthritis Rheum.30, 1205–1213). By contrast, virtually no cleavage of the same peptide was observed with IgG from healthy controls. A peptide analog, Gln−Arg−Arg−Trp−Ala, was not cleaved at all by any IgGs examined either from RA patients or healthy controls.

Molecular evolution in the hypervariable regions of fetuin: comparison between human and African green monkey fetuin.

Abstract Sequences of fetuin cDNA and its deduced amino acid residues from the African green monkey cell line Vero were found to differ by 7.3% and 12.9%, respectively, from the corresponding human sequences. Most amino acid substitutions were clustered within a small segment of the third domain (D3). Calculations of nonsynonymous and synonymous nucleotide substitution rates suggest that this small segment was mutated under positive selection. cDNAs encoding α1-antitrypsin, β-actin and the sequences of intron 4 of α1-antitrypsin gene in human liver and Vero cells were also investigated. The results substantiated the positive selection imposed on the D3 segment.

Is the Catalytic Activity of Bence Jones Proteins an Autoimmune Effector Mechanism in Multiple Myeloma

On Friday, October 30, 1845, W. MacIntire, physician to the Metropolitan Convalescent Institution and to the Western General Dispensary, St. Marylebone, was called to see a patient who had been treated by T. Watson for several months (1,2). Since the patient had a history of edema, Maclntire examined the urine and noted the peculiar physical properties of the urinary protein (precipitation with heating at 40–60°C, disappearance with boiling, and reappearance with cooling). He wrote: “I was at first inclined to think that some mistake had occurred, but on repeated trials with other specimens, and closely watching their course, the results were always found to be the same” (2). Watson had evidently not examined the urine when the patient had been under his care, but was present when Maclntire performed urinalysis. In those days, it was customary for the specialist services to be provided by practicing physicians and surgeons. Urine specimens were sent to Henry Bence Jones, physician to St. George’s Hospital and professor of forensic medicine of the Medical College associated with the Hospital. Jones was then 31 yr old, but had already established a reputation as a chemical pathologist. He confirmed the Maclntire results and examined the protein in some detail. The patient died six weeks later, and an autopsy was performed by Shaw, surgeon to the Middlesex Hospital, in the presence of Watson, Jones, Ridge, and Maclntire, none of whom thought that the peculiar urinary protein was related to the disease, mollities ossium, later called multiple myeloma (2).