01. Gene therapy Boulikas.pdf - Gene therapy & Molecular Biology

B. Approaches to gene therapy of RA
The current emphasis for RA gene therapy is on
transferring genes encoding secreted proteins which
possess antiarthritic properties. Genes may be delivered
locally to individual diseased joints or systemically to
extra-articular sites where the secreted gene products may
enter the circulation. Gene transfer to the synovium would
ensure local production of anti-inflammatory gene
products directly in the articular space where they could
exert a down-regulatory effect on the autoimmune process.
Although adenoviral delivery appeared best suited for
gene delivery to synovium, induction of an inflammatory
response resulting in loss of gene expression may take
place (Evans and Robbins, 1996).
High efficiency lacZ gene transfer and expression was
achieved in both type A and type B synoviocytes
throughout the articular and periarticular synovium of the
rabbit knee by Roessler et al (1993). Intra-articular
administration of an E1a-E3-deleted adenoviral (Ad5)
vector expressing the lacZ transgene into mouse joints
showed lacZ expression in the articular synovium for at
least 14 days. However, a gradual loss of transgene
expression was caused by a predominantly neutrophilic,
inflammatory response. Pretreatment with the anti-T cell
receptor monoclonal antibody (mAb) H57 resulted in a
significant reduction in lymphocytic infiltration and in
persistence of transgene expression. Thus, anti-T cell
mAbs may be useful in inhibiting adenovirus-induced
immune responses that lead to the loss of therapeutically
transduced cells (Sawchuk et al, 1996).
Many new therapeutic approaches are currently being
developed, including the use of soluble receptors to IL-1
or TNF, monoclonal antibodies to TNF-α, and a specific
IL-1 receptor antagonist. A number of studies have
assessed the impact of gene transfer on inflammatory and
chondrodestructive effects during the acute phase of
antigen-induced arthritis in RA joints. A promising
therapy for RA involves delivery of the TNF-α and IL-1
proteins to the joints to inhibit the activity of
proinflammatory cytokines (Bandara et al, 1993; Arend
and Dayer, 1995).
Angiogenesis is not only essential for the growth and
metastatic spread of solid tumors but in diseases such as
rheumatoid arthritis, psoriasis, liver cirrhosis and diabetic
retinopathy (Norrby, 1997). Future approaches for the
gene therapy of RA may thus include anti-angiogenesis
approaches to the inflamed joints.
Gene Therapy and Molecular Biology Vol 1, page 113
113
C. Ex vivo gene therapy of RA using IL-
1Ra-transduced cells
Degradation of cartilage in RA in vitro is stimulated by
IL-1, a proinflammatory cytokine, which is released from
RA synovial fibroblasts (RA-SF). Synovial cells were
surgically removed from joints of animals with
experimental arthritis, cultured and transduced with the
naturally occurring inhibitor of IL-1, IL-1-receptor
antagonist (IL-1Ra) protein gene and reimplanted into the
respective donors by intra-articular injection (Bandara et
al, 1993). Retroviral transfer of the IL-1Ra gene to RA-SF
which were then coimplanted with normal human cartilage
in SCID mice protected the cartilage from chondrocytemediated
degradation; the IL-1Ra-transduced RA-SF
continued to secrete IL-1Ra over a 60-day period (Muller-
Ladner et al, 1997a,b). Transfer the human IL-1Ra gene to
rabbits' knees produced a marked chondroprotective effect
although the anti-inflammatory effect was milder (Otani et
al, 1996).
Ex vivo retroviral delivery of the secreted human IL-
1Ra cDNA to primary synoviocytes followed by
engraftment in ankle joints of rats with recurrent bacterial
cell wall-induced arthritis significantly suppressed the
severity of recurrence of arthritis as assessed by measuring
joint swelling and by the gross-observation score; this ex
vivo approach attenuated but did not abolish erosion of
cartilage and bone; the level of locally expressed IL-1Ra
was about four orders of magnitude higher than that
attained from systemically administered recombinant IL-
1Ra protein (Makarov et al, 1996). These findings provide
experimental evidence for the feasibility of
antiinflammatory gene therapy for arthritis.
Retroviral transduction of hematopoietic stem cells
with human IL-1Ra cDNA was also used for the treatment
of RA; HSCs were subsequently injected into lethally
irradiated mice; all of the mice survived and over 98% of
the white blood cells in these mice were arising from the
transduced HSCs (donor type) from 2-13 months after
transplantation; the animals had the human IL-1Ra protein
in their sera for at least 15 months. These results
demonstrated that systemic production of biologically
active human IL-1Ra can be obtained by retrovirusmediated
gene transfer to hematopoietic stem cells which
could be useful in the treatment of chronic diseases such
as rheumatoid arthritis as well as bone degeneration
caused by aging (Boggs et al, 1995).
Characterization of the interleukin-1/interleukin-1
receptor antagonist pathways in RA resulted in the first
gene therapy trial in animals and humans for RA (Evans et
al, 1996; reviewed by Evans and Robbins, 1996; Muller-
Ladner et al, 1997a). Protocol #56 (page 162) involves
removal of autologous synovial cells from the patient,
their retroviral transduction with the IL-1Ra cDNA
followed by injection of the transduced cells into the
metacarpal phalangeal joints of RA patients.