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1.
J Ultrasound ; 2024 Apr 07.
Article in English | MEDLINE | ID: mdl-38583119

ABSTRACT

PURPOSE: Ultrasound (US) surveillance is a cornerstone for early diagnosis of HCC, anyway US presentation has undergone significant changes. With the aim of evaluating the effects of US surveillance program in the real-world clinical practice, we wanted to evaluate US presentation of HCCs over the last 30 years and the differences of HCCs presentation according to etiology. METHODS: 174 patients diagnosed between 1993 and 98 (G1), 96 between 2003 and 08 (G2), 102 between 2013 and 18 (G3), were compared. US patterns were: single, multiple or diffuse nodules. The echo-patterns: iso-, hypo-, hyper-echoic, or mixed. In G1, the HCC diagnosis was mainly histologic; in G2 by EASL 2001 and AASLD 2005, in G3 AASLD 2011, EASL 2012, and AISF 2013 guidelines. RESULTS: HCV was the most frequent etiology, dropping between G1 (81%) and G3 (66%) (P < 0.01), metabolic increased between G1 (5%) and G3 (14%) (P < 0.01). Single HCC was more prevalent in G3 vs G1 (65.6% vs 40%) (P < 0.0001), multiple nodules in G1 (50%) vs G3 (33.3%) (P < 0.02) and diffuse in G1 (16%) vs G2 (2%) and vs G3 (1%) (P < 0.001). The most frequent echo-pattern was hypo-echoic G1 (50%) vs G2 (79%) and G1 vs G3 (65%) (P < 0.01). Iso-echoic pattern was the least frequent (7-12%). Mixed pattern decreased from G1 (28%) to G3 (12%) (P < 0.002). In G3 there were more multiple or diffuse HCCs in metabolic (P < 0.03). CONCLUSION: US presentation became less severe due to surveillance programs. HCV remains the most frequent cause, an increase in metabolic etiology has been shown throughout the decades.

2.
Sci Rep ; 14(1): 9303, 2024 04 23.
Article in English | MEDLINE | ID: mdl-38654033

ABSTRACT

Remdesivir (RDV) was the first Food and Drug Administration (FDA)-approved medication for COVID-19, with discordant data on efficacy in reducing mortality risk and disease progression. In the context of a dynamic and rapidly changing pandemic landscape, the utilization of real-world evidence is of utmost importance. The objective of this study is to evaluate the impact of RDV on patients who have been admitted to two university referral hospitals in Italy due to COVID-19. All patients older than 18 years and hospitalized at two different universities (Bari and Palermo) were enrolled in this study. To minimize the effect of potential confounders, we used propensity score matching with one case (Remdesivir) and one control that never experienced this kind of intervention during hospitalization. Mortality was the primary outcome of our investigation, and it was recorded using death certificates and/or medical records. Severe COVID-19 was defined as admission to the intensive care unit or a qSOFAscore ≥ 2 or CURB65scores ≥ 3. After using propensity score matching, 365 patients taking Remdesivir and 365 controls were included. No significant differences emerged between the two groups in terms of mean age and percentage of females, while patients taking Remdesivir were less frequently active smokers (p < 0.0001). Moreover, the patients taking Remdesivir were less frequently vaccinated against COVID-19. All the other clinical, radiological, and pharmacological parameters were balanced between the two groups. The use of Remdesivir in our cohort was associated with a significantly lower risk of mortality during the follow-up period (HR 0.56; 95% CI 0.37-0.86; p = 0.007). Moreover, RDV was associated with a significantly lower incidence of non-invasive ventilation (OR 0.27; 95% CI 0.20-0.36). Furthermore, in the 365 patients taking Remdesivir, we observed two cases of mild renal failure requiring a reduction in the dosage of Remdesivir and two cases in which the physicians decided to interrupt Remdesivir for bradycardia and for QT elongation. Our study suggests that the use of Remdesivir in hospitalized COVID-19 patients is a safe therapy associated with improved clinical outcomes, including halving of mortality and with a reduction of around 75% of the risk of invasive ventilation. In a constantly changing COVID-19 scenario, ongoing research is necessary to tailor treatment decisions based on the latest scientific evidence and optimize patient outcomes.


Subject(s)
Adenosine Monophosphate , Adenosine Monophosphate/analogs & derivatives , Alanine , Alanine/analogs & derivatives , Antiviral Agents , COVID-19 Drug Treatment , COVID-19 , Propensity Score , Humans , Alanine/therapeutic use , Adenosine Monophosphate/therapeutic use , Female , Male , Italy/epidemiology , Middle Aged , Aged , Antiviral Agents/therapeutic use , COVID-19/mortality , COVID-19/epidemiology , Hospitalization/statistics & numerical data , SARS-CoV-2 , Treatment Outcome , Aged, 80 and over , Adult , Retrospective Studies
3.
Nutrients ; 16(2)2024 Jan 12.
Article in English | MEDLINE | ID: mdl-38257142

ABSTRACT

Metabolic syndrome (MetS) is associated with cardiovascular risk factors, such as insulin resistance, dyslipidaemia, hypertension and abdominal obesity. Given the growing need to investigate food supplements with positive health effects, this study was aimed at testing the benefits of a specific supplement for people with MetS. Fifty-eight subjects with MetS and T2DM or impaired glucose tolerance assuming metformin, were randomly assigned to take a food supplement of glucomannan, D-chiro-inositol, Cinnamomum zeylanicum blume and inulin at a daily fixed dose of 4 g orally for four months. Body weight, waist circumference, plasma lipid profile (total cholesterol, LDL, HDL and triglyc-erides), plasma glycaemic profile and visceral adiposity index (VAI) were measured at baseline and after four months of supplementation. After 16 weeks, in subjects with T2DM or insulin resistance who took the supplement (+ metformin), there was a significant reduction in body weight and BMI (p < 0.0001), serum insulin (p < 0.05) and the HOMA index (p < 0.01), as well as in the lipaemic pattern, with a significant improvement in total serum cholesterol (p < 0.005), triglycerides (p < 0.03) and LDL (p < 0.02). Our study shows that the food supplement tested is a valid and safe alternative therapeutic approach in the management of MetS and all its resulting risk factors, as its efficacy has been demonstrated across anthropometric, glucose, lipid and hepatic parameters.


Subject(s)
Diabetes Mellitus, Type 2 , Insulin Resistance , Mannans , Metabolic Syndrome , Metformin , Humans , Metabolic Syndrome/drug therapy , Cinnamomum zeylanicum , Inulin , Inositol , Dietary Supplements , Body Weight , Lipids
4.
Int J Mol Sci ; 24(20)2023 Oct 23.
Article in English | MEDLINE | ID: mdl-37895163

ABSTRACT

In the last decade, an increasing awareness was directed to the role of Vitamin D in non-skeletal and preventive roles for chronic diseases. Vitamin D is an essential hormone in regulating calcium/phosphorous balance and in the pathogenesis of inflammation, insulin resistance, and obesity. The main forms of vitamin D, Cholecalciferol (Vitamin D3) and Ergocalciferol (Vitamin D2) are converted into the active form (1,25-dihydroxyvitamin D) thanks to two hydroxylations in the liver, kidney, pancreas, and immune cells. Some anti-inflammatory cytokines are produced at higher levels by vitamin D, while some pro-inflammatory cytokines are released at lower levels. Toll-Like Receptor (TLR) expression is increased, and a pro-inflammatory state is also linked to low levels of vitamin D. Regardless of how it affects inflammation, various pathways suggest that vitamin D directly improves insulin sensitivity and secretion. The level of vitamin D in the body may change the ratio of pro- to anti-inflammatory cytokines, which would impact insulin action, lipid metabolism, and the development and function of adipose tissue. Many studies have demonstrated an inverse relationship between vitamin D concentrations and pro-inflammatory markers, insulin resistance, glucose intolerance, metabolic syndrome, obesity, and cardiovascular disease. It is interesting to note that several long-term studies also revealed an inverse correlation between vitamin D levels and the occurrence of diabetes mellitus. Vitamin D supplementation in people has controversial effects. While some studies demonstrated improvements in insulin sensitivity, glucose, and lipid metabolism, others revealed no significant effect on glycemic homeostasis and inflammation. This review aims to provide insight into the molecular basis of the relationship between vitamin D, insulin resistance, metabolic syndrome, type 1 and 2 diabetes, gestational diabetes, and cardiovascular diseases.


Subject(s)
Cardiovascular Diseases , Diabetes Mellitus, Type 1 , Diabetes Mellitus, Type 2 , Insulin Resistance , Metabolic Syndrome , Vitamin D Deficiency , Pregnancy , Female , Humans , Vitamin D/therapeutic use , Metabolic Syndrome/complications , Cardiovascular Diseases/complications , Diabetes Mellitus, Type 1/complications , Diabetes Mellitus, Type 2/metabolism , Insulin/metabolism , Vitamin D Deficiency/metabolism , Vitamins/therapeutic use , Cholecalciferol/therapeutic use , Obesity/complications , Inflammation/complications , Cytokines/therapeutic use , Anti-Inflammatory Agents/therapeutic use
5.
PLoS Pathog ; 19(7): e1011486, 2023 07.
Article in English | MEDLINE | ID: mdl-37459364

ABSTRACT

Trypanosoma brucei is a single celled eukaryotic parasite in the group of the Kinetoplastea. The parasite harbors a single mitochondrion with a singular mitochondrial genome that is known as the kinetoplast DNA (kDNA). The kDNA consists of a unique network of thousands of interlocked circular DNA molecules. To ensure proper inheritance of the kDNA to the daughter cells, the genome is physically linked to the basal body, the master organizer of the cell cycle in trypanosomes. The connection that spans, cytoplasm, mitochondrial membranes and the mitochondrial matrix is mediated by the Tripartite Attachment Complex (TAC). Using a combination of proteomics and RNAi we test the current model of hierarchical TAC assembly and identify TbmtHMG44 and TbKAP68 as novel candidates of a complex that connects the TAC to the kDNA. Depletion of TbmtHMG44 or TbKAP68 each leads to a strong kDNA loss but not missegregation phenotype as previously defined for TAC components. We demonstrate that the proteins rely on both the TAC and the kDNA for stable localization to the interface between these two structures. In vitro experiments suggest a direct interaction between TbmtHMG44 and TbKAP68 and that recombinant TbKAP68 is a DNA binding protein. We thus propose that TbmtHMG44 and TbKAP68 are part of a distinct complex connecting the kDNA to the TAC.


Subject(s)
DNA, Mitochondrial , Trypanosoma brucei brucei , DNA, Mitochondrial/genetics , Trypanosoma brucei brucei/genetics , Trypanosoma brucei brucei/metabolism , DNA, Kinetoplast/genetics , DNA, Kinetoplast/metabolism , Mitochondria/genetics , Mitochondria/metabolism , DNA-Binding Proteins/metabolism , Protozoan Proteins/metabolism , DNA Replication
6.
Int J Mol Sci ; 24(2)2023 Jan 15.
Article in English | MEDLINE | ID: mdl-36675242

ABSTRACT

The immune response to infection plays a crucial role in the pathogenesis of COVID-19, but several patients develop a wide range of persistent symptoms, which is becoming a major global health and economic burden. However, reliable indicators are not yet available to predict the persistence of symptoms typical of the so-called long COVID. Our study aims to explore an eventual role of IL-6 levels as a marker of long COVID. Altogether, 184 patients admitted to the COVID Medicine Unit of the University Hospital in Palermo, Italy, from the 1st of September 2020, were analyzed. Patients were divided into two groups according to the IL-6 serum levels (normal or elevated), considering the serum IL-6 levels measured during the first four days of hospitalization. In our study, higher serum IL-6 levels were associated with a doubled higher risk of long COVID (OR = 2.05; 95% CI: 1.04-4.50) and, in particular, they were associated with a higher incidence of mobility decline (OR = 2.55; 95% CI: 1.08-9.40) and PTSD (OR = 2.38; 95% CI: 1.06-8.61). The analysis of our case series confirmed the prominent role of IL-6 levels in response to SARS-CoV-2 infection, as predictors not only of COVID-19 disease severity and unfavorable outcomes, but also long COVID development trends.


Subject(s)
COVID-19 , Humans , SARS-CoV-2 , Post-Acute COVID-19 Syndrome , Interleukin-6 , Hospitalization
8.
FEMS Microbiol Rev ; 47(6)2023 11 01.
Article in English | MEDLINE | ID: mdl-36449697

ABSTRACT

Mitochondrial DNA replication is an essential process in most eukaryotes. Similar to the diversity in mitochondrial genome size and organization in the different eukaryotic supergroups, there is considerable diversity in the replication process of the mitochondrial DNA. In this review, we summarize the current knowledge of mitochondrial DNA replication and the associated factors in trypanosomes with a focus on Trypanosoma brucei, and provide a new model of minicircle replication for this protozoan parasite. The model assumes the mitochondrial DNA (kinetoplast DNA, kDNA) of T. brucei to be loosely diploid in nature and the replication of the genome to occur at two replication centers at the opposing ends of the kDNA disc (also known as antipodal sites, APS). The new model is consistent with the localization of most replication factors and in contrast to the current model, it does not require the assumption of an unknown sorting and transport complex moving freshly replicated DNA to the APS. In combination with the previously proposed sexual stages of the parasite in the insect vector, the new model provides a mechanism for maintenance of the mitochondrial genetic diversity.


Subject(s)
DNA, Kinetoplast , Genome, Mitochondrial , DNA, Kinetoplast/genetics , Genome, Mitochondrial/genetics , DNA Replication/genetics , DNA, Mitochondrial/genetics , Mitochondria/genetics , Protozoan Proteins/genetics
9.
Int J Mol Sci ; 23(17)2022 Sep 04.
Article in English | MEDLINE | ID: mdl-36077515

ABSTRACT

Type 2 diabetes mellitus (T2DM) is a serious public health concern as it is one of the most common chronic diseases worldwide due to social and economic developments that have led to unhealthy lifestyles, with a considerable impact both in terms of morbidity and mortality. The management of T2DM, before starting specific therapies, includes cornerstones such as healthy eating, regular exercise and weight loss. Strict adherence to the Mediterranean diet (MedDiet) has been related to an inverse association with the risk of T2DM onset, as well as an improvement in glycaemic control; in particular, thanks to the consumption of extra virgin olive oil (EVOO). Agonists of gut-derived glucagon-like peptide-1 (GLP-1), gastrointestinal hormones able to increase insulin secretion in response to hyperglycaemia (incretins), have been recently introduced in T2DM therapy, quickly entering the international guidelines. Recent studies have linked the action of EVOO in reducing postprandial glycaemia to the increase in GLP-1 and the reduction of its inactivating protease, dipeptidyl peptidase-4 (DPP-4). In this review, we explore observations regarding the pathophysiological basis of the existence of an enhanced effect between the action of EVOO and incretins and, consequently, try to understand whether there is a rationale for their use in combination for T2DM therapy.


Subject(s)
Diabetes Mellitus, Type 2 , Dipeptidyl-Peptidase IV Inhibitors , Blood Glucose , Diabetes Mellitus, Type 2/drug therapy , Dipeptidyl-Peptidase IV Inhibitors/pharmacology , Dipeptidyl-Peptidase IV Inhibitors/therapeutic use , Glucagon-Like Peptide 1/physiology , Humans , Hypoglycemic Agents , Incretins/therapeutic use , Insulin Secretion
11.
Int J Mol Sci ; 23(7)2022 Mar 27.
Article in English | MEDLINE | ID: mdl-35409028

ABSTRACT

Non-alcoholic fatty liver disease (NAFLD), the most frequent liver disease in the Western world, is a common hepatic manifestation of metabolic syndrome (MetS). A specific cure has not yet been identified, and its treatment is currently based on risk factor therapy. Given that the initial accumulation of triglycerides in the liver parenchyma, in the presence of inflammatory processes, mitochondrial dysfunction, lipotoxicity, glucotoxicity, and oxidative stress, can evolve into non-alcoholic steatohepatitis (NASH). The main goal is to identify the factors contributing to this evolution because, once established, untreated NASH can progress through fibrosis to cirrhosis and, ultimately, be complicated by hepatocellular carcinoma (HCC). Several drugs have been tested in clinical trials for use as specific therapy for NAFLD; most of them are molecules used to cure type 2 diabetes mellitus (T2DM), which is one of the main risk factors for NAFLD. Among the most studied is pioglitazone, either alone or in combination with vitamin E, glucagon-like peptide-1 (GLP-1) receptor agonists, dipeptidyl peptidase-4 (DPP-4) inhibitors. Actually, the most promising category seems to be sodium-glucose cotransporter (SGLT2) inhibitors. Their action is carried out by inhibiting glucose reabsorption in the proximal renal tubule, leading to its increased excretion in urine and decreased levels in plasma. Experimental studies in animal models have suggested that SGLT2 inhibitors may have beneficial modulatory effects on NAFLD/NASH, and several trials in patients have proven their beneficial effects on liver enzymes, BMI, blood lipids, blood glucose, and insulin resistance in NAFLD patients, thus creating strong expectations for their possible use in preventing the evolution of liver damage in these patients. We will review the main pathogenetic mechanisms, diagnostic modalities, and recent therapies of NAFLD, with particular attention to the use of SGLT2 inhibitors.


Subject(s)
Carcinoma, Hepatocellular , Diabetes Mellitus, Type 2 , Dipeptidyl-Peptidase IV Inhibitors , Liver Neoplasms , Non-alcoholic Fatty Liver Disease , Sodium-Glucose Transporter 2 Inhibitors , Animals , Carcinoma, Hepatocellular/drug therapy , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/metabolism , Dipeptidyl-Peptidase IV Inhibitors/therapeutic use , Glucose/therapeutic use , Humans , Hypoglycemic Agents/adverse effects , Liver/metabolism , Liver Neoplasms/drug therapy , Non-alcoholic Fatty Liver Disease/complications , Sodium-Glucose Transporter 2 Inhibitors/pharmacology , Sodium-Glucose Transporter 2 Inhibitors/therapeutic use
12.
Intern Emerg Med ; 17(1): 43-51, 2022 Jan.
Article in English | MEDLINE | ID: mdl-33909256

ABSTRACT

Management for HCV has undergone a notable change using direct-acting antiviral drugs (DAAs), which are safe and effective even in elderly. Here, we define impact of comorbidities, concomitant medication and drug-drug interactions in elder patients with HCV related disease before starting DAAs regimen. We analyzed data of 814 patients prospectively enrolled at our Unit within the web based model HCV Sicily Network. Out of 814, 590 were treated with DAAs and 414 of them were older than 65 years. We divided those 414 in two groups, one including 215 patients, aged between 65 and 74 years, and another with 199 patients, aged of 75 years and over. Charlson Comorbidity Index (CCI) was assessed for each patient; drug-drug interactions (DDI) and de-prescribing process were carried out appropriately. Within 414 patients included, percentage rates of women treated was higher than males, BMI was lower and cirrhosis was frequently reported in patients older than 75 years. Hypertension, diabetes mellitus, dyslipidemia (p < 0.0001), prostatic pathologies, kidney disease, gastrointestinal disease (p < 0.0001), osteoporosis (p < 0.01) and depression were most common co-morbidities. CCI showed lower scores in the first group as compared with the second one (p < 0.0001). Among drugs, statins were frequently suspended and anti-hypertensive often replaced. DAAs are useful and effective regardless of disease severity, comorbidities, medications and age. De-prescribing allows a stable reduction of number of medications taken with real improvement of quality of life.


Subject(s)
Antiviral Agents , Hepatitis C, Chronic , Aged , Antiviral Agents/therapeutic use , Comorbidity , Female , Hepacivirus , Hepatitis C, Chronic/drug therapy , Humans , Male , Prospective Studies , Quality of Life
13.
J Cell Sci ; 134(5)2021 03 08.
Article in English | MEDLINE | ID: mdl-33589495

ABSTRACT

Proper mitochondrial genome inheritance is important for eukaryotic cell survival. Trypanosoma brucei, a protozoan parasite, contains a singular mitochondrial genome, the kinetoplast (k)DNA. The kDNA is anchored to the basal body via the tripartite attachment complex (TAC) to ensure proper segregation. Several components of the TAC have been described; however, the connection of the TAC to the kDNA remains elusive. Here, we characterize the TAC-associated protein TAP110. We find that both depletion and overexpression of TAP110 leads to a delay in the separation of the replicated kDNA networks. Proteome analysis after TAP110 overexpression identified several kDNA-associated proteins that changed in abundance, including a TEX-like protein that dually localizes to the nucleus and the kDNA, potentially linking replication and segregation in the two compartments. The assembly of TAP110 into the TAC region seems to require the TAC but not the kDNA itself; however, once TAP110 has been assembled, it also interacts with the kDNA. Finally, we use ultrastructure expansion microscopy in trypanosomes for the first time, and reveal the precise position of TAP110 between TAC102 and the kDNA, showcasing the potential of this approach.This article has an associated First Person interview with the first author of the paper.


Subject(s)
Genome, Mitochondrial , Trypanosoma brucei brucei , DNA, Kinetoplast/genetics , Genome, Mitochondrial/genetics , Mitochondria , Protozoan Proteins/genetics , Trypanosoma brucei brucei/genetics
14.
Biomed Res Int ; 2020: 5309307, 2020.
Article in English | MEDLINE | ID: mdl-32185209

ABSTRACT

AIMS: To analyze the main etiological factors and some clinical features of patients with hepatocellular carcinoma (HCC) at diagnosis and to compare them with those we described ten years ago. Materials and Methods. We compared two groups of patients with HCC, Group 1 consisting of 132 patients (82 M, 50 F) diagnosed in the 2003-2008 period and Group 2 including 119 patients (82 M, 37 F) diagnosed in the 2013-2018 period. For all patients, age, sex, viral markers, alcohol consumption, serum alpha-fetoprotein (AFP) levels, and the main liver function parameters were recorded. The diagnosis of HCC was based on AASLD, EASL guidelines. The staging was classified according to the "Barcelona Clinic Liver Cancer staging system" (BCLC). RESULTS: Mean age was 69.0 ± 8 years in Group 1 and 71.0 ± 9 in Group 2 (P < 0.05). HCV subjects were significantly older in Group 2 (P < 0.05). HCV subjects were significantly older in Group 2 (P < 0.05). HCV subjects were significantly older in Group 2 (P < 0.05). HCV subjects were significantly older in Group 2 (P < 0.05). HCV subjects were significantly older in Group 2 (P < 0.05). HCV subjects were significantly older in Group 2 (P < 0.05). HCV subjects were significantly older in Group 2 (P < 0.05). HCV subjects were significantly older in Group 2 (. CONCLUSIONS: This study shows that over the last decade a number of features of patients with HCC in our region have changed, particularly age at onset, etiological factors, and staging of HCC.


Subject(s)
Carcinoma, Hepatocellular/epidemiology , Liver Neoplasms/epidemiology , Aged , Carcinoma, Hepatocellular/etiology , Carcinoma, Hepatocellular/metabolism , Carcinoma, Hepatocellular/pathology , Female , Hepatitis B/complications , Hepatitis C/complications , Humans , Liver Neoplasms/etiology , Liver Neoplasms/metabolism , Liver Neoplasms/pathology , Male , Neoplasm Staging/methods , Risk Factors , alpha-Fetoproteins/metabolism
15.
Microb Cell ; 5(10): 460-468, 2018 Aug 24.
Article in English | MEDLINE | ID: mdl-30386790

ABSTRACT

The translationally controlled tumor protein TCTP, is a universally conserved protein that seems to be of essential function in all systems tested so far. TCTP is involved in a multitude of cellular functions including cell cycle control, cell division, apoptosis and many more. The mechanism of how TCTP is involved in most of these functions remains elusive. Here we describe that TCTP is a cytoplasmic protein involved in cell cycle regulation and heat stress response in the bloodstream form of Trypanosoma brucei.

16.
J Cell Sci ; 131(9)2018 05 10.
Article in English | MEDLINE | ID: mdl-29661850

ABSTRACT

The translationally controlled tumor protein (TCTP; also known as TPT1 in mammals) is highly conserved and ubiquitously expressed in eukaryotes. It is involved in growth and development, cell cycle progression, protection against cellular stresses and apoptosis, indicating the multifunctional role of the protein. Here, for the first time, we characterize the expression and function of TCTP in the human and animal pathogen, Trypanosoma brucei We identified two paralogs (TCTP1 and TCTP2) that are differentially expressed in the life cycle of the parasite. The genes have identical 5' untranslated regions (UTRs) and almost identical open-reading frames. The 3'UTRs differ substantially in sequence and length, and are sufficient for the exclusive expression of TCTP1 in procyclic- and TCTP2 in bloodstream-form parasites. Furthermore, we characterize which parts of the 3'UTR are needed for TCTP2 mRNA stability. RNAi experiments demonstrate that TCTP1 and TCTP2 expression is essential for normal cell growth in procyclic- and bloodstream-form parasites, respectively. Depletion of TCTP1 in the procyclic form cells leads to aberrant cell and mitochondrial organelle morphology, as well as enlarged, and a reduced number of, acidocalcisomes.


Subject(s)
Biomarkers, Tumor/biosynthesis , Protozoan Proteins/biosynthesis , Trypanosoma brucei brucei/genetics , Trypanosoma brucei brucei/metabolism , 3' Untranslated Regions , Biomarkers, Tumor/genetics , Life Cycle Stages/physiology , Protozoan Proteins/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Tumor Protein, Translationally-Controlled 1
17.
J Cell Sci ; 131(8)2018 04 25.
Article in English | MEDLINE | ID: mdl-29626111

ABSTRACT

The unicellular parasite Trypanosoma brucei harbors one mitochondrial organelle with a singular genome called the kinetoplast DNA (kDNA). The kDNA consists of a network of concatenated minicircles and a few maxicircles that form the kDNA disc. More than 30 proteins involved in kDNA replication have been described. However, several mechanistic questions are only poorly understood. Here, we describe and characterize minicircle replication factor 172 (MiRF172), a novel mitochondrial genome replication factor that is essential for cell growth and kDNA maintenance. By performing super-resolution microscopy, we show that MiRF172 is localized to the kDNA disc, facing the region between the genome and the mitochondrial membranes. We demonstrate that depletion of MiRF172 leads to a loss of minicircles and maxicircles. Detailed analysis suggests that MiRF172 is involved in the reattachment of replicated minicircles to the kDNA disc. Furthermore, we provide evidence that the localization of the replication factor MiRF172 not only depends on the kDNA itself, but also on the mitochondrial genome segregation machinery, suggesting an interaction between the two essential entities.This article has an associated First Person interview with the first author of the paper.


Subject(s)
DNA Replication , DNA, Kinetoplast/metabolism , DNA, Mitochondrial/metabolism , DNA-Binding Proteins/genetics , Genome, Mitochondrial , Trypanosoma brucei brucei/genetics , Animals , DNA, Kinetoplast/genetics , DNA, Mitochondrial/genetics , DNA-Binding Proteins/metabolism , Trypanosoma brucei brucei/metabolism
18.
Proc Natl Acad Sci U S A ; 115(8): E1809-E1818, 2018 02 20.
Article in English | MEDLINE | ID: mdl-29434039

ABSTRACT

In almost all eukaryotes, mitochondria maintain their own genome. Despite the discovery more than 50 y ago, still very little is known about how the genome is correctly segregated during cell division. The protozoan parasite Trypanosoma brucei contains a single mitochondrion with a singular genome, the kinetoplast DNA (kDNA). Electron microscopy studies revealed the tripartite attachment complex (TAC) to physically connect the kDNA to the basal body of the flagellum and to ensure correct segregation of the mitochondrial genome via the basal bodies movement, during the cell cycle. Using superresolution microscopy, we precisely localize each of the currently known TAC components. We demonstrate that the TAC is assembled in a hierarchical order from the base of the flagellum toward the mitochondrial genome and that the assembly is not dependent on the kDNA itself. Based on the biochemical analysis, the TAC consists of several nonoverlapping subcomplexes, suggesting an overall size of the TAC exceeding 2.8 mDa. We furthermore demonstrate that the TAC is required for correct mitochondrial organelle positioning but not for organelle biogenesis or segregation.


Subject(s)
Gene Expression Regulation/physiology , Genome, Mitochondrial/physiology , Genome, Protozoan/physiology , Trypanosoma brucei brucei/genetics , DNA, Kinetoplast/genetics , Models, Biological
19.
Sci Rep ; 6: 36565, 2016 11 22.
Article in English | MEDLINE | ID: mdl-27874016

ABSTRACT

Mitochondrial organelles need to be replicated during cell division. Many aspects of this process have been studied in great detail, however the actual size increase and the position of organelle growth are less well understood. We use the protozoan parasite Trypanosoma brucei that contains a single mitochondrion to study organelle biogenesis by fluorescence microscopy. From the analysis of more than 1000 T. brucei bloodstream form cells of a nonsynchronous population we conclude that the mitochondrial network mostly grows from two areas along the main organelle axis, posterior and anterior of the nucleus. Loops and branches from these two areas eventually fuse to build a complex network. Together with the appearance of the division fold in the posterior part of the cell, pruning of the mitochondrial network and finally separation into the two daughter cells occurs. Overall organelle biogenesis is not continuous during cell growth and occurs mostly in the last part of the cell cycle. Furthermore, using 3D STED super resolution microscopy we reconstruct the volume of the organelle and characterize the region where the mitochondrial genome is positioned by serial block face scanning electron microscopy.


Subject(s)
Cell Cycle/physiology , Mitochondria/physiology , Mitochondrial Dynamics/physiology , Trypanosoma brucei brucei/metabolism , Trypanosoma brucei brucei/cytology
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