Identification of Several Isoforms of T-Kininogen Expressed in the Liver of Aging Rats

doi:10.1006/abbi.1995.1472

Archives of Biochemistry and Biophysics

Volume 322, Issue 2, 1 October 1995, Pages 333-338

https://doi.org/10.1006/abbi.1995.1472 Get rights and content

Abstract

We have previously shown that senescent Sprague-Dawley rats have significantly increased levels of kininogen (KG) mRNA and protein, when compared with younger counterparts. In the rat, five different isoforms of kininogen have been identified: high-molecular-weight K-kininogen, low-molecular-weight K-kininogen, and T1α, T1β, and T2 kininogens. Several of these isoforms have been shown to differ in their biological properties. It was therefore considered relevant to establish which of these isoforms are expressed in the liver of old rats. To this end, we have isolated and sequenced nine independent cDNA clones from a library constructed using liver mRNA from healthy senescent rats. Predicted protein sequences indicate the presence of T-kininogens only. The relative lack of induction of K-kininogens during aging was further confirmed by RNA hybridization experiments. The nucleotide sequences reveal a microheterogeneity of silent polymorphisms, suggesting the presence and expression of several different alleles of the genes. From our data we conclude that (i) Several isoforms of TKG are expressed in the liver of senescent Sprague-Dawley rats and (ii) T1 kininogens appear to be the most highly represented T-KG mRNA species in old rat livers.

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Cited by (3)

Prospective highlights of serum glycoproteins in spontaneous tolerance after orthotopic liver transplantation
2011, Clinica Chimica Acta
Citation Excerpt :
In rats, five different isoforms of kininogen were identified. T-kininogen is a cysteine proteinase inhibitor and also serves as a reliable biomarker of the aging process in male Sprague–Dawley rats [20]. T-kininogen expression may indicate the involvement of vasodilatation, thereby favouring the deposition of immune complexes at the vascular level [21].
We examined the effects and the mechanisms of serum glycoproteins on spontaneous tolerance after orthotopic liver transplantation (OLT) between DA (RT-1^a) and PVG (RT-1^c) rats.
A functional proteome analysis was introduced to investigate differently expressed proteins involved in overcoming major histocompatibility complex (MHC) barriers and lectin blotting was applied to survey the levels of fucosylated proteins.
Two-dimensional difference gel electrophoresis (2D-DIGE) coupled with mass spectrometry revealed statistically significant changes in the intensity of 19 proteins at 14 and 60 post-OLT days which respectively corresponded to rejection and tolerance. An interaction network analysis of the identified proteins indicated that the interleukin (IL)-6 signaling pathway might be correlated with the immune events in this model. The peak of IL-6 expression occurred during the recovery period might play a role in the remarkable shifts in the immune response towards spontaneous tolerance. Furthermore, increased levels of IL-6-modulated fucosylation of Igh-6 were also observed during the rejection response while fucosylated hemopexin and haptoglobin were obviously upregulated in the tolerogenic period.
These findings suggest that IL-6 and glycoproteins may play critical roles in this spontaneous tolerogenic DA/PVG OLT model and shed light on prolonging hepatic allograft survival in the future.
Kininogens: More than cysteine protease inhibitors and kinin precursors
2010, Biochimie
Citation Excerpt :
A unique protease inhibitor is over-expressed in prostate during senescence and corresponds to both T-I and T-II forms of TK [192]. No variation of HK expression was detected in prostates of senescent rats, while a greater HK level was reported in sera of aged rats [177]. While there is one report that HK rises linearly with age in humans [193], a possible age-related increase in the expression and function of human kininogens remains an intriguing question.
Two kininogens are found in mammalian sera: HK (high molecular weight kininogen) and LK (low molecular weight kininogen) with the exception of the rat which encompasses a third kininogen, T-Kininogen (TK). Kininogens are multifunctional glycosylated molecules related to cystatins (clan IH, family I25). They harbor three cystatin domains but only two of them are tight-binding inhibitors of cysteine cathepsins. HK and LK, but not TK, are precursors of potent peptide hormones, the kinins, which are released proteolytically by tissue and plasma kallikreins. Besides these classical features novel functions of kininogens have been recently discovered; they are described in the second part of this review. HKa, which corresponds to the kinin-free two-chain HK and its isolated domain D5 (kininostatin), possesses angiostatic and pro-apoptotic properties, inhibits the proliferation of endothelial cells and participates in the regulation of angiogenesis. Moreover, some HK-derived peptides display potent and broad-spectrum microbicidal properties against both Gram-positive and Gram-negative bacteria, and thus may offer a promising alternative to conventional antibiotic therapy. Of seminal interest, a kininogen-derived peptide inhibits activation of the contact phase system of coagulation and protects mice with invasive Streptococcus pyogenes infection from pulmonary lesions. On the other hand, TK is a biomarker of aging at the end of lifespan of elderly rats. However, although TK has been initially identified as an acute phase reactant, and earlier known as alpha-l-acute phase globulin, the increase of TK in liver and plasma is not known to relate to any inflammatory event during the senescence process.
T-Kininogen present in the liver of old rats is biologically active and readily forms complexes with endogenous cysteine proteinases
1997, Mechanisms of Ageing and Development
We have previously reported an increase in T-kininogen mRNA levels in the liver of ageing Sprague-Dawley rats. T-Kininogen functions both as a precursor to the vasoactive peptide T-kinin, and as a potent and specific inhibitor of cysteine proteinases. Under normal physiological conditions, the majority of cysteine proteinases are found intracellularly and we have shown that a significant proportion of T-kininogen also accumulates intracellularly in the liver of old rats. Therefore, our aim was to determine whether or not this T-kininogen is biologically active as an inhibitor of cysteine proteases. Titration of whole liver extracts indicates that old rats do indeed contain a 4-fold higher level of cysteine proteinase inhibitory activity than younger counterparts. Using gel permeation chromatography in conjunction with an enzyme inhibitor assay, we show that this difference is mainly due to the presence of a low level of free biologically active T-kininogen. However, Western blot analysis of the gel permeation chromatography fractions demonstrate that most of the intrahepatic T-kininogen is found as enzyme-inhibitor complexes. Alkaline inactivation of the cysteine proteinase component of these complexes leads to the release of biologically competent free T-kininogen. These findings are discussed with regard to the possible mechanisms responsible for the accumulation of T-kininogen within the aged rat liver.

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Regular ArticleIdentification of Several Isoforms of T-Kininogen Expressed in the Liver of Aging Rats

Abstract

Regular Article
Identification of Several Isoforms of T-Kininogen Expressed in the Liver of Aging Rats