Chemistry: molecular biology and microbiology – Animal cell – per se ; composition thereof; process of...
Reexamination Certificate
1998-07-30
2001-01-09
Chin, Christopher L. (Department: 1641)
Chemistry: molecular biology and microbiology
Animal cell, per se ; composition thereof; process of...
C435S440000, C435S455000, C435S183000, C435S234000, C435S235100, C435S252300, C435S253300, C435S254110, C435S372300, C435S320100, C435S317100, C435S173300, C435S069100, C435S069700, C435S242000, C435S003000, C435S014000, C435S034000, C435S176000, C435S320100, C435S375000, C435S366000, C435S069400, C435S030000, C424S094400, C424S093210, C424S093300, C424S204100, C424S196110, C424S225100, C514S009100, C514S010100, C514S014800, C514S564000, C514S031000, C514S169000, C514S806000
Reexamination Certificate
active
06171856
ABSTRACT:
1. Field of the Invention
The present invention relates generally to the fields of molecular biology. More particularly, it concerns the use of superoxide dismutase compositions to modulate cytokine mediated cytotoxicity. It also concerns techniques for the modulation of fatty acid-mediated lipotoxicity.
2. Description of Related Art
There is considerable evidence that classifies insulin-dependent diabetes mellitus (IDDM; type I diabetes) as a chronic autoimmune disease. IDDM occurs when insulin-producing islet &bgr;-cells are destroyed by autoimmune mechanisms (Castano and Eisenbarth, 1994; Rossini et al., 1991). This destruction leads to insulin deficiency, and acute metabolic abnormalities develop which will likely led to death in the absence of insulin therapy. Patients of type I diabetes are at constant risk from hypoglycemia from pharmacological intervention with insulin, with the majority of such individuals developing an alarming plethora of complications.
Significant evidence has accumulated in support of an important role for inflammatory cytokines, particularly IL-1&bgr;, as immunological effector molecules that induce dysfunction and destruction of the pancreatic &bgr;-cell (Mandrup-Poulsen, 1996; Rabinovitch, 1993). It has been proposed that cytokine-induced destruction of islet &bgr;-cells is mediated in part by generation of toxic oxygen radicals (Mandrup-Poulsen et al., 1987; Malaisse et al. 1982). Islet &bgr;-cells may be particularly susceptible to this mechanism of destruction due to unusually low levels of expression of enzymes involved in metabolism of reactive oxygen species, including superoxide dismutase, catalase, and various peroxidases (Malaisse et al. 1982; Asayama et al. 1986; Lenzen et al., 1995).
There are conflicting reports of the relative importance of oxygen radicals in islet cell destruction, making the field very unclear. One group reported that external application of chemical oxygen radical scavengers provided protection against cytokine killing (Sumoski, et al. 1989), while others using external application of superoxide dismutase or catalase reported no protective effect (Burkart and Kolb, 1993; Yamada et al. 1993).
The effects of a number of cytokines, including IL-1&bgr;, on islet &bgr;-cells also have been linked to induction of the inducible form of nitric oxide synthase (iNOS) and production of nitric oxide (NO) (Mandrup-Poulsen, 1996; Corbett and McDaniel, 1992; Eizirik et al., 1996). Indeed, inhibitors of iNOS effectively block both the short term metabolic and long-term cytotoxic effects of IL-1&bgr; on islet cells (Southern et al., 1990; Corbett and McDaniel, 1994).
An unresolved and important issue in this area is whether the induction of MnSOD in islets in response to cytokines represents a protective mechanism against free radical toxicity or is instead contributory to &bgr;-cell destruction. As pointed out by Eizirik and coworkers (Hakan Borg et al., 1992), induction of MnSOD could cause accumulation of NO by removal of the superoxide ion that would otherwise be free to react with NO to form peroxynitrite, a byproduct that has direct &bgr;-cell cytotoxic effects (Delaney et al., 1996). Thus, induction of MnSOD could either serve to lower the levels of toxic oxygen radicals and/or peroxynitrite (protective effect) or increase NO (potentially cytotoxic). These events are clearly important in IDDM.
NIDDM is another form of diabetes that occurs through &bgr;-cell destruction. The Zucker Diabetic Fatty (ZDF) rat provides a useful replica of the human phenotype of adipogenic NIDDM in which to study the islets (Peterson et al., 1990). Such studies implicate fat deposition in islets as the cause of the &bgr;-cell decompensation, so-called “lipotoxicity” (Lee et al., 1994; Unger, 1995).
&bgr;-cell decompensation in this form of diabetes may involve exaggerated induction by FFA of inducible nitric oxide synthase (iNOS) and excess nitric oxide (NO) generation (Shimabukuro et al., 1997a, 1997b). Because intracellular NO is an important mediator of programmed cell death (Moncada et al., 1991; Corbett et al., 1992; Kaneto et al., 1995), it seems possible that the loss of the &bgr;-cells observed late in the course of adipogenic NIDDM (Ohneda et al., 1995) might be the result of NO-induced apoptosis. Apoptosis has been reported in fat-laden hepatocytes (Yang et al., 1997).
Thus, it is clear that there is a need for information that provides a clue as to how &bgr;-cells are destroyed. In particular, it is necessary to pinpoint the involvement of NO cytotoxicity in &bgr;-cell dysfunction and destruction with a view to treatment and prophylaxis of diabetes.
SUMMARY OF THE INVENTION
In one embodiment, the present invention provides a method of protecting a mammalian cell against immunotoxicity comprising introducing into the mammalian cell an antioxidizing agent; wherein the antioxidizing agent protects the cell against immunotoxicity. In preferred embodiments, the immunotoxicity may be cytokine-mediated immunotoxicity. In particularly preferred embodiments, the immunotoxicity may be mediated by IL-1&bgr;, IL-1&agr;, &ggr;IFN, TNF-&agr;, TNF-&bgr;, an IL-8, an IL-12, IL-6, IL-2, IL-3, IL-5, IL-7, IL-9, IL-14, IL-17, granulocyte-macrophage colony stimulating factor or monocyte chemoattractant protein-1. In more particularly preferred embodiments, the cytokine is IL-1&bgr;.
In another embodiment, the present invention provides a method of protecting a mammalian cell against lipotoxicity comprising introducing into the mammalian cell an agent that protects the cell against lipotoxicity. In a particularly preferred embodiment, lipotoxicity may be mediated by free fatty acids or conjugated fatty acids. Conjugated fatty acids are well known to those of skill in the art, and include triglycerides, ceramides (and other sphingolipids), phospholipids and the like.
In certain aspects of the invention, the antioxidizing agent may be a protein. In other aspects, the antioxidizing agent may be a small molecule antioxidizing agent. In those embodiments in which the antioxidizing agent is a protein, the antioxidizing agent is introduced through an antioxidixing agent-encoding gene operatively linked to a first promoter. In particular embodiments, the antioxidizing agent may be selected from the group consisting of a superoxide dismutase, a catalase, glutathione peroxidase, Bcl-2, Mcl-1, &agr;-melanocyte stimulating hormone, &agr;-glycoprotein, a cytoprotective cytokine, DT-diaphorase, and epoxide hydrolase. In those embodiments in which the antioxidant is a small molecule, the antioxidizing agent may be selected from the group consisting of Vitamin C, Vitamin E, nicotinamide, troglitazone, aminoguanidine and uric acid.
In particular embodiments, the method may further comprise introducing into the cell, a therapeutic gene operatively linked to a second promoter. In more particular embodiments, the therapeutic gene may encodes insulin, growth hormone, prolactin, placental lactogen, luteinizing hormone, follicle-stimulating hormone, chorionic gonadotropin, thyroid-stimulating hormone, LCAT, adrenocorticotropin (ACTH), angiotensin I, angiotensin II, &bgr;-endorphin, &bgr;-melanocyte stimulating hormone (&bgr;-MSH), cholecystokinin, endothelin I, galanin, gastric inhibitory peptide (GIP), IGF-1, glucagon, amylin, lipotropins, neurophysins, GLP-1, leptin, leptin receptor, calcitonin and somatostatin.
In certain embodiments, the therapeutic gene and the antioxidizing agent-encoding gene are contained in the same vector. In other embodiments, therapeutic gene and the antioxidizing agent-encoding gene are contained in distinct vectors. In more particular embodiments, the first promoter may be inducible. In specific embodiments, the first promoter may be selected from the group consisting of CMV IE, SV40 IE, RSV LTR, RIP, modified RIP, POMC, &bgr;gal, lac operon, ecdysone-inducible expression system, tetracyline operon, glucocorticoid response element, heat shock promoter and growth hormone promoter. In other embodiments, the second promoter may selected from the gr
Chen Guoxun
Cousin Sharon
Hohmeier Hans-Ewald
H{umlaut over (u)}gl Sigrun R.
Newgard Christopher B.
Board of Regents , The University of Texas System
Chin Christopher L.
Cook Lisa V.
Fulbright & Jaworski LLP
LandOfFree
Methods and compositions relating to no-mediated cytotoxicity does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Methods and compositions relating to no-mediated cytotoxicity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Methods and compositions relating to no-mediated cytotoxicity will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2440911