Researchers have successfully treated hereditary hearing loss in mice using a small molecule of a drug leading to hopes for new matibabu for deafness
Kupoteza kusikia au uziwi is caused by genetic inheritance in more than 50 percent of people. It is the most common birth defect which can unborn babies. Hereditary genetic conditions are responsible for kuzaliwa hearing loss and contribute to more 50% cases of deafness in new-borns and infants. Such hearing loss affects members within a family since a person may inherit a mutated gene or genes or an undesirable gene causing this loss to occur. The inherited hearing loss present at birth also accompanies other afya masuala kama vile tatizo la kuona na usawa katika angalau asilimia 30 ya matukio. Hata wakati mzao haonyeshi ugonjwa wa kusikia, anaweza kurithi mabadiliko ya jeni. Hii ina maana kwamba mtu ni carrier. Mbebaji wa mabadiliko ya jeni yasiyotakikana anaweza kuipitisha kwa watoto wajao ambao wanaweza kupoteza kusikia. Uziwi huu kwa kiasi kikubwa hautibiki.
Katika utafiti uliochapishwa katika Kiini, wanasayansi katika Chuo Kikuu cha Iowa na Taasisi ya Kitaifa ya Viziwi na Matatizo Mengine ya Mawasiliano, wamegundua kwa mara ya kwanza dawa ya molekuli ndogo ambayo inaweza kuhifadhi kusikia kwa panya wanaosumbuliwa na urithi wa uziwi wa binadamu unaoendelea. Watafiti waliweza kurejesha usikivu kwa sehemu katika masafa madogo ya sauti na pia kuokoa chache za "seli za nywele za hisi" ndani ya sikio la ndani. Utafiti huu haujatoa tu mwanga juu ya utaratibu kamili wa molekuli ambayo inasisitiza aina hii mahususi ya uziwi wa kijeni (inayoitwa DFNA27) lakini inapendekeza matibabu ya madawa yanayoweza kuishughulikia.
Utafiti huo ulianza wakati watafiti walijaribu kuchambua msingi wa kijeni wa aina hii ya uziwi iliyorithiwa muongo mmoja uliopita. Walichunguza taarifa za kinasaba za wanafamilia (inayojulikana kama LMG2). Uziwi ulitawala katika familia hii yaani walibeba jeni kubwa la uziwi na watoto wowote walihitaji tu kurithi nakala moja ya jeni mbovu kutoka kwa mama au baba kuwa na aina hii ya uziwi. Katika uchunguzi wao uliochukua takriban muongo mmoja, watafiti waligundua mabadiliko ambayo yalisababisha uziwi kwenye "eneo" linaloitwa DFNA27. Eneo hili lilijumuisha karibu jeni kadhaa ambazo zikibadilishwa zinaweza kusababisha upotezaji wa kusikia, kwa hivyo eneo kamili la mabadiliko bado halijaonyeshwa. Seti ya tafiti za baadaye zilisaidia kubainisha panya Restgene (RE1 Silencing Transcription Factor) na watafiti waligundua kuwa jeni la panya Rest hudhibitiwa na mchakato usio wa kawaida katika seli za hisi za sikio na hii ni muhimu sana kwa utendaji wa kusikia wa mamalia. Watafiti kisha walianza kuchunguza eneo la DFNA27 kwani ilionekana kuwa jeni la Rest la binadamu liko katika eneo hili pekee. Mara tu mahali na kazi ya Restgene ilipoeleweka vyema, uchambuzi zaidi ulifanyika ili kuona ni nini kinachoweza kurekebisha jeni hili na kusaidia kuboresha uziwi.
Restgene basi ilibadilishwa ili kuunda kielelezo cha uziwi ambacho majaribio yangeweza kufanywa. Ilionekana kuwa seli za nywele za hisi ziliharibiwa ndani ya sikio la ndani la panya na kuwafanya kuwa viziwi. Mabadiliko sawa yalipatikana katika familia ya LMG2 pia. Udanganyifu ulipobadilishwa, protini ya REST huzimwa na jeni nyingi zikiwashwa na kusababisha ufufuaji wa seli za nywele za hisi na kusaidia panya kusikiliza vyema. Kwa hivyo, ufunguo ni protini ya REST iliyosimbwa na jeni la Rest. Protini hii kawaida hukandamiza jeni kwa njia inayoitwa "histone deacetylation". Watafiti walitumia molekuli ndogo ya dawa ambayo inaweza "kufanya kama swichi" na inaweza kuzuia mchakato huu wa uharibifu wa histone na hivyo kuzima protini ya REST. Kuzima jeni la Rest kisha kuruhusu seli mpya za nywele kujengwa ambazo hatimaye zilirejesha kusikia kwa panya.
This is an important and relevant study in analysing the internal mechanisms which define hereditary type of deafness. Although this study has been conducted in mice, the strategies uncovered here could be utilized for binadamu testing. It is a fine starting point to perform additional studies in which small molecule-based madawa ya kulevya can be shown to be effective in treating DFNA27 deafness. This study could be also potentially be extended to other types of progressive hearing loss caused by inheriting jeni. The genetic leads provide more information to uncover novel pathways for designing potential treatments for hearing loss in humans. Also, more small molecules could be used in the future to treat inherited deafness.
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Chanzo (s)
Nakano Y et al 2018. Kasoro katika Udhibiti Mbadala Unaotegemea Ugawanyiko wa REST Husababisha Uziwi. Kiini.
https://doi.org/10.1016/j.cell.2018.06.004
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