The maintenance of K+ and Ca2+ homeostasis is crucial for many cellular functions. Potassium is accumulated in cells at high concentrations, while the cytosolic level of calcium, to ensure its signalling function, is kept at low levels and transiently increases in response to stresses. We examined Ca2+ homeostasis and Ca2+ signalling in Saccharomyces cerevisiae strains lacking plasma-membrane K+ influx (Trk1 and Trk2) or efflux (Tok1, Nha1 and Ena1-5) systems. The lack of K+ exporters slightly increased the cytosolic Ca2+, but did not alter the Ca2+ tolerance or Ca2+-stress response. In contrast, the K+-importers Trk1 and Trk2 play important and distinct roles in the maintenance of Ca2+ homeostasis. The presence of Trk1 was vital mainly for the growth of cells in the presence of high extracellular Ca2+, whilst the lack of Trk2 doubled steady-state intracellular Ca2+ levels. The absence of both K+ importers highly increased the Ca2+ response to osmotic or CaCl2 stresses and altered the balance between Ca2+ flux from external media and intracellular compartments. In addition, we found Trk2 to be important for the tolerance to high KCl and hygromycin B in cells growing on minimal media. All the data describe new interconnections between potassium and calcium homeostasis in S. cerevisiae.

• MeSH
• chlorid draselný farmakologie   MeSH
• cinnamáty farmakologie   MeSH
• draslík metabolismus   MeSH
• homeostáza * MeSH
• hygromycin B analogy a deriváty   farmakologie   MeSH
• proteiny přenášející kationty genetika   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae účinky léků   genetika   metabolismus   MeSH
• signální transdukce * MeSH
• vápník metabolismus   farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Úvod: Vstup viru lidské imunitní nedostatečnosti typu 1 (HIV-1) do cílových buněk je umožněn CD4 receptorem a jedním ze dvou koreceptorů CXCR4 nebo CCR5. Delece úseku 32 nukleotidů v genu pro CCR5 (CCR5Δ32) v obou alelách poskytuje silnou, avšak ne absolutní odolnost proti infekci HIV-1 a delece v jedné alele zpomaluje postup nemoci směřující k rozvinutí AIDS. Zde jsme analyzovali prevalenci a roli heterozygotního výskytu CCR5Δ32 na postup onemocnění u HIV pozitivních jedinců v České republice. Metody: Celkem 92 HIV-1 séropozitivních osob včetně 80 Čechů z AIDS centra v Nemocnici Na Bulovce v Praze bylo zařazeno do genotypizace CCR5, která byla součástí studie role HIV fitness na průběh onemocnění. Z periferních mononukleárních buněk pacienta byla získána DNA, která byla použita k amplifikaci pomocí PCR v reálném čase použitím specifických sond, které detekovaly divokou variantu CCR5 a variantu s 32 nt delecí. Podmnožina 74 pacientů bez antiretrovirové léčby, kteří byli sledováni déle než jeden rok, byla použita k určení role heterozygotního fenotypu CCR5 na průběh nemoci. Výsledky: Heterozygotní CCR5Δ32 varianta byla nalezena u 23,8 % z 80 českých HIV-1 séropozitivních osob, což je velmi podobné jako publikovaná 21 % a 24 % prevalence u HIV negativní české populace. Homozygotní mutovaná varianta nebyla nalezena. U skupiny osob s heterozygotním CCR5 fenotypem jsme pozorovali slabě zvýšený průměrný počet CD4-pozitivních T-lymfocytů a nižší průměrné hodnoty virémie v plazmě. Závěr: Celkově, naše studie neukázala žádný zřejmý užitek přítomnosti heterozygotní CCR5Δ32 varianty na přenos HIV a pouze malý užitek na průběh nemoci u české HIV-1 pozitivní kohorty.

Background: Entry of human immunodeficiency virus type 1 (HIV-1) in target cells is enabled by CD4 receptor and one of two co-receptors, CXCR4 or CCR5. Deletion of 32 bp in CCR5 gene (CCR5Δ32) in both alleles provides strong but not absolute resi-stance to HIV-1 infection and deletion in one allele slows disease progression to AIDS. Here, we analyzed the prevalence and the role of CCR5Δ32 heterozygosity on the disease progression in HIV positive patients in the Czech Republic. Patients and methods: A total of 92 HIV-1 seropositive subjects that included 80 Czech individuals from the AIDS center in the Hospital Na Bulovce in Prague were enrolled in CCR5 genoty-ping as a part of a study of the role of HIV fitness on disease progression. DNA was extracted from patient’s peripheral blood mononuclear cells and subjected to real-time PCR with specific probes detecting wild-type and 32 bp-deleted CCR5 variants. A subgroup of 74 antiretroviral therapy-naive patients with more than one year of follow-up was used to determine the role of the CCR5Δ32 heterozygous phenotype in disease progression. Results: CCR5Δ32 was found heterozygous in 23.8% of 80 Czech HIV-1 seropositive individuals which is very similar to 21% and 24% prevalence reported in HIV negative Czech population. Homozygous mutant variant was not detected. In CCR5Δ32 he-terozygous group we observed slightly higher mean CD4+ T-cell count and lower mean plasma viremia levels.Conclusions: Overall, our study indicates no obvious benefit of CCR5Δ32 heterozygosity on HIV transmission and only small benefit on disease progression in the Czech HIV-1 cohort.

• MeSH
• genotypizační techniky MeSH
• HIV-1 * genetika   izolace a purifikace   MeSH
• kohortové studie MeSH
• lidé MeSH
• polymorfismus genetický MeSH
• progrese nemoci MeSH
• receptory CCR5 genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

BACKGROUND: Progression rates from initial HIV-1 infection to advanced AIDS vary significantly among infected individuals. A distinct subgroup of HIV-1-infected individuals-termed viremic non-progressors (VNP) or controllers-do not seem to progress to AIDS, maintaining high CD4+T cell counts despite high levels of viremia for many years. Several studies have evaluated multiple host factors, including immune activation, trying to elucidate the atypical HIV-1 disease progression in these patients; however, limited work has been done to characterize viral factors in viremic controllers. METHODS: We analyzed HIV-1 isolates from three VNP individuals and compared the replicative fitness, near full-length HIV-1 genomes and intra-patient HIV-1 genetic diversity with viruses from three typical (TP) and one rapid (RP) progressor individuals. RESULTS: Viremic non-progressors and typical patients were infected for >10 years (range 10-17 years), with a mean CD4+T-cell count of 472 cells/mm3(442-529) and 400 cells/mm3(126-789), respectively. VNP individuals had a less marked decline in CD4+cells (mean -0.56, range -0.4 to -0.7 CD4+/month) than TP patients (mean -10.3, -8.2 to -13.1 CD4+/month). Interestingly, VNP individuals carried viruses with impaired replicative fitness, compared to HIV-1 isolates from the TP and RP patients (p < 0.05, 95% CI). Although analyses of the near full-length HIV-1 genomes showed no clear patterns of single-nucleotide polymorphisms (SNP) that could explain the decrease in replicative fitness, both the number of SNPs and HIV-1 population diversity correlated inversely with the replication capacity of the viruses (r = -0.956 andr = -0.878,p < 0.01, respectively). CONCLUSION: It is likely that complex multifactorial parameters govern HIV-1 disease progression in each individual, starting with the infecting virus (phenotype, load, and quasispecies diversity) and the intrinsic ability of the host to respond to the infection. Here we analyzed a subset of viremic controller patients and demonstrated that similar to the phenomenon observed in patients with a discordant response to antiretroviral therapy (i.e., high CD4+cell counts with detectable plasma HIV-1 RNA load), reduced viral replicative fitness seems to be linked to slow disease progression in these antiretroviral-naïve individuals.

• MeSH
• dlouhodobě přežívající nosiči HIV * MeSH
• dospělí MeSH
• genetická variace MeSH
• genetická zdatnost * MeSH
• genom virový MeSH
• HIV infekce virologie   MeSH
• HIV-1 klasifikace   genetika   izolace a purifikace   fyziologie   MeSH
• kohortové studie MeSH
• lidé středního věku MeSH
• lidé MeSH
• replikace viru * MeSH
• sekvenční analýza DNA MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH