Mice disrupted for the KvLQT1 potassium channel regulator IsK gene accumulate mature T cells

A novel cancer syndrome caused by KCNQ1-deficiency in the golden Syrian hamster

BACKGROUND

The golden Syrian hamster is an emerging model organism. To optimize its use, our group has made the first genetically engineered hamsters. One of the first genes that we investigated is KCNQ1 which encodes for the KCNQ1 potassium channel and also has been implicated as a tumor suppressor gene.

MATERIALS AND METHODS

We generated KCNQ1 knockout (KO) hamsters by CRISPR/Cas9-mediated gene targeting and investigated the effects of KCNQ1-deficiency on tumorigenesis.

RESULTS

By 70 days of age seven of the eight homozygous KCNQ1 KOs used in this study began showing signs of distress, and on necropsy six of the seven ill hamsters had visible cancers, including T-cell lymphomas, plasma cell tumors, hemangiosarcomas, and suspect myeloid leukemias.

CONCLUSIONS

None of the hamsters in our colony that were wild-type or heterozygous for KCNQ1 mutations developed cancers indicating that the cancer phenotype is linked to KCNQ1-deficiency. This study is also the first evidence linking KCNQ1-deficiency to blood cancers.

Phenotypic Analysis of Vertigo 2 Jackson Mice with a Kcnq1 Potassium Channel Mutation

The KCNQ1 gene encodes a voltage-dependent potassium ion channel, and mutations in this gene are the most common cause of congenital long QT syndrome (LQTS). In the present study, we investigated the various phenotypic characteristics of vertigo 2 Jackson (C3H/HeJCrl-Kcnq1(vtg-2J)/J) mice with a Kcnq1 mutation. Both heterozygotes (vtg-2J/+) and homozygotes (vtg-2J/vtg-2J) showed prolonged QT intervals in electrocardiograms (ECGs) compared to C3H/HeJ control (+/+) mice. Furthermore, vtg-2J/vtg-2J mice showed gastric achlorhydria associated with elevation of their serum gastrin levels. The serum corticosterone levels were also significantly increased in vtg-2J/vtg-2J mice. In addition, vtg-2J/vtg-2J mice exhibited significantly higher blood pressure. These findings indicate that the Kcnq1 mutation in vtg-2J mice alters various physiological functions in the cardiac, gastric and adrenocortical systems, and suggest that vtg-2J mice may represent a useful model for studying Kcnq1 functions.

The multifaceted phenotype of the knockout mouse for the KCNE1 potassium channel gene

Mutations of the KCNE1 gene (IsK, minK) are related to hereditary forms of cardiac arrhythmias, so-called long QT syndromes (LQT). Here we review the phenotype of a mouse model for the recessive form of LQT known as Jervell and Lange-Nielsen syndrome. KCNE1 knockout mice exhibit an enhanced QT-RR adaptability, which is probably part of the pathophysiological mechanism leading to life-threatening tachyarrhythmia in patients. Like patients, knockout mice are deaf and show vestibular symptoms due to an impaired endolymph production. Knockout mice show urinary and fecal salt wasting and volume depletion. The renal phenotype is due to diminished reabsorption of Na(+) and glucose. The mice are hypokalemic and have increased aldosterone levels. Besides volume depletion, aldosterone is elevated via a set-point shift for sensing of extracellular K(+) in aldosterone-secreting glomerulosa cells, which physiologically express KCNE1. In conclusion, KCNE1 knockout leads to a complex phenotype resulting from direct loss of KCNE1 and compensatory mechanisms. Murine KCNE1 physiology could be helpful for the pathophysiological understanding and perhaps gene-specific treatment of long QT patients.