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1.
ACS Infect Dis ; 2024 May 16.
Article in English | MEDLINE | ID: mdl-38752809

ABSTRACT

Malaria parasites have a complex life cycle and undergo replication and population expansion within vertebrate hosts and mosquito vectors. These developmental transitions rely on changes in gene expression and chromatin reorganization that result in the activation and silencing of stage-specific genes. The ApiAp2 family of DNA-binding proteins plays an important role in regulating gene expression in malaria parasites. Here, we characterized the ApiAp2 protein in Plasmodium berghei, which we termed Ap2-D. In silico analysis revealed that Ap2-D has three beta-sheets followed by a helix at the C-terminus for DNA binding. Using gene tagging with 3XHA-mCherry, we found that Ap2-D is expressed in Plasmodium blood stages and is present in the parasite cytoplasm and nucleus. Surprisingly, our gene deletion study revealed a completely dispensable role for Ap2-D in the entirety of the P. berghei life cycle. Ap2-D KO parasites were found to grow in the blood successfully and progress through the mosquito midgut and salivary glands. Sporozoites isolated from mosquito salivary glands were infective for hepatocytes and achieved similar patency as WT in mice. We emphasize the importance of genetic validation of antimalarial drug targets before progressing them to drug discovery.

3.
Mol Microbiol ; 121(5): 940-953, 2024 May.
Article in English | MEDLINE | ID: mdl-38419272

ABSTRACT

Plasmodium is an obligate intracellular parasite that requires intense lipid synthesis for membrane biogenesis and survival. One of the principal membrane components is oleic acid, which is needed to maintain the membrane's biophysical properties and fluidity. The malaria parasite can modify fatty acids, and stearoyl-CoA Δ9-desaturase (Scd) is an enzyme that catalyzes the synthesis of oleic acid by desaturation of stearic acid. Scd is dispensable in P. falciparum blood stages; however, its role in mosquito and liver stages remains unknown. We show that P. berghei Scd localizes to the ER in the blood and liver stages. Disruption of Scd in the rodent malaria parasite P. berghei did not affect parasite blood stage propagation, mosquito stage development, or early liver-stage development. However, when Scd KO sporozoites were inoculated intravenously or by mosquito bite into mice, they failed to initiate blood-stage infection. Immunofluorescence analysis revealed that organelle biogenesis was impaired and merozoite formation was abolished, which initiates blood-stage infections. Genetic complementation of the KO parasites restored merozoite formation to a level similar to that of WT parasites. Mice immunized with Scd KO sporozoites confer long-lasting sterile protection against infectious sporozoite challenge. Thus, the Scd KO parasite is an appealing candidate for inducing protective pre-erythrocytic immunity and hence its utility as a GAP.


Subject(s)
Liver , Malaria , Merozoites , Organelle Biogenesis , Plasmodium berghei , Sporozoites , Stearoyl-CoA Desaturase , Plasmodium berghei/genetics , Plasmodium berghei/growth & development , Plasmodium berghei/metabolism , Plasmodium berghei/enzymology , Animals , Mice , Liver/parasitology , Merozoites/growth & development , Merozoites/metabolism , Malaria/parasitology , Stearoyl-CoA Desaturase/metabolism , Stearoyl-CoA Desaturase/genetics , Sporozoites/growth & development , Sporozoites/metabolism , Protozoan Proteins/metabolism , Protozoan Proteins/genetics , Anopheles/parasitology , Female , Endoplasmic Reticulum/metabolism
5.
ACS Infect Dis ; 10(4): 1116-1125, 2024 Apr 12.
Article in English | MEDLINE | ID: mdl-38421807

ABSTRACT

The O-fucosylation of the thrombospondin type I repeat (TSR) domain is important for TSR-containing proteins' optimal folding and stability. However, the importance of Plasmodium O-fucosyltransferase 2 (POFut2) remains unclear due to two different reports. Here, we disrupted the POFut2 gene in Plasmodium berghei and demonstrated that POFut2 KO parasites develop normally in blood and mosquito stages but show reduced infectivity in mice. We found that the reduced infectivity of POFut2 KO sporozoites was due to a diminished level of TRAP that affected the parasite gliding motility and hepatocyte infectivity. Using all-atom MD simulation, we also hypothesize that O-fucosylation impacts the TSR domain's stability more than its heparin binding capacity.


Subject(s)
Fucosyltransferases , Plasmodium berghei , Animals , Mice , Fucosyltransferases/genetics , Fucosyltransferases/metabolism , Plasmodium berghei/genetics , Sporozoites , Protozoan Proteins/metabolism , Hepatocytes/parasitology
6.
mBio ; 15(4): e0023224, 2024 Apr 10.
Article in English | MEDLINE | ID: mdl-38411954

ABSTRACT

Neddylation is a type of posttranslational modification known to regulate a wide range of cellular processes by covalently conjugating the ubiquitin-like protein Nedd8 to target proteins at lysine residues. However, the role of neddylation in malaria parasites has not been determined. Here, for the first time, we showed that neddylation plays an essential role in malaria transmission in Plasmodium berghei. We found that disruption of Nedd8 did not affect blood-stage propagation, gametocyte development, gamete formation, or zygote formation while abolishing the formation of ookinetes and further transmission of the parasites in mosquitoes. These phenotypic defects in Nedd8 knockout parasites were complemented by reintroducing the gene that restored mosquito transmission to wild-type levels. Our data establish the role of P. berghei Nedd8 in malaria parasite transmission.IMPORTANCENeddylation is a process by which Nedd8 is covalently attached to target proteins through three-step enzymatic cascades. The attachment of Nedd8 residues results in a range of diverse functions, such as cell cycle regulation, metabolism, immunity, and tumorigenesis. The potential neddylation substrates are cullin (CUL) family members, which are implicated in controlling the cell cycle. Cullin neddylation leads to the activation of cullin-RING ubiquitin ligases, which regulate a myriad of biological processes through target-specific ubiquitylation. Neddylation possibly regulates meiosis in zygotes, which subsequently develop into ookinetes. Our findings point to an essential function of this neddylation pathway and highlight its possible importance in designing novel intervention strategies.


Subject(s)
Plasmodium berghei , Ubiquitins , Animals , Ubiquitins/genetics , Ubiquitins/metabolism , Plasmodium berghei/genetics , Plasmodium berghei/metabolism , Cullin Proteins/metabolism , Ubiquitin/metabolism , Ubiquitin-Protein Ligases/metabolism
7.
Soft Matter ; 20(4): 869-876, 2024 Jan 24.
Article in English | MEDLINE | ID: mdl-38170915

ABSTRACT

An elastic biopolymer, resilin possesses exceptional qualities such as high stretchability and resilience. Such attributes are utilized in nature by many species for mechanical energy storage to facilitate movement. The properties of resilin are attributed to the balanced combination of hydrophilic and hydrophobic segments. To mimic the properties of resilin, we developed a hydrogel system composed of hydrophilic acrylic acid (AAc) and methacrylamide (MAM) chains and hydrophobic poly(propylene glycol diacrylate) (PPGDA) chains. The gel was produced through free-radical polymerization in 0.8 M NaCl solutions using KPS as an initiator. In these gels, AAc and MAM can form hydrogen bonds, whereas the association between PPGDA chains can lead to hydrophobic domains. The PPGDA concentration affects the level of hydrogen bonding and gel mechanical properties. Tensile experiments revealed that the elastic modulus increased with a higher PPGDA concentration. Retraction experiments demonstrated increased velocity and acceleration when released from a stretched state with increasing PPGDA concentration. Swelling and deswelling of gels in saline solutions led to a change in mechanical properties and retraction behavior. This study shows that the stretchability and resilience of these hydrogels can be adjusted by changing the concentration of hydrophobic components.

8.
BMC Health Serv Res ; 24(1): 123, 2024 Jan 23.
Article in English | MEDLINE | ID: mdl-38263183

ABSTRACT

BACKGROUND: The world population is ageing rapidly. Rehabilitation is one of the most effective health strategies for improving the health and functioning of older persons. An understanding of the current provision of rehabilitation services in primary care (PC) is needed to optimise access to rehabilitation for an ageing population. The objectives of this scoping review are a) to describe how rehabilitation services are currently offered in PC to older persons, and b) to explore age-related differences in the type of rehabilitation services provided. METHODS: We conducted a secondary analysis of a scoping review examining rehabilitation models for older persons, with a focus on PC. Medline and Embase (2015-2022) were searched to identify studies published in English on rehabilitation services for people aged 50 + . Two authors independently screened records and extracted data using the World Health Organization (WHO)'s operational framework, the Primary Health Care Systems (PRIMASYS) approach and the WHO paper on rehabilitation in PC. Data synthesis included quantitative and qualitative analysis. RESULTS: We synthesised data from 96 studies, 88.6% conducted in high-income countries (HICs), with 31,956 participants and identified five models for delivering rehabilitation to older persons in PC: community, home, telerehabilitation, outpatient and eldercare. Nurses, physiotherapists, and occupational therapists were the most common providers, with task-shifting reported in 15.6% of studies. The most common interventions were assessment of functioning, rehabilitation coordination, therapeutic exercise, psychological interventions, and self-management education. Environmental adaptations and assistive technology were rarely reported. CONCLUSIONS: We described how rehabilitation services are currently provided in PC and explored age-related differences in the type of rehabilitation services received. PC can play a key role in assessing functioning and coordinating the rehabilitation process and is also well-placed to deliver rehabilitation interventions. By understanding models of rehabilitation service delivery in PC, stakeholders can work towards developing more comprehensive and accessible services that meet the diverse needs of an ageing population. Our findings, which highlight the role of rehabilitation in healthy ageing, are a valuable resource for informing policy, practice and future research in the context of the United Nations Decade of Healthy Ageing, the Rehab2030 initiative and the recently adopted WHA resolution on strengthening rehabilitation in health systems, but the conclusions can only be applied to HICs and more studies are needed that reflect the reality in low- and middle-income countries.


Subject(s)
Medicine , Occupational Therapy , Self-Help Devices , Humans , Aged , Aged, 80 and over , Exercise Therapy , Primary Health Care
9.
Cell Mol Life Sci ; 80(11): 344, 2023 Nov 01.
Article in English | MEDLINE | ID: mdl-37910326

ABSTRACT

During macroautophagy, the Atg8 protein is conjugated to phosphatidylethanolamine (PE) in autophagic membranes. In Apicomplexan parasites, two cysteine proteases, Atg4 and ovarian tumor unit (Otu), have been identified to delipidate Atg8 to release this protein from membranes. Here, we investigated the role of cysteine proteases in Atg8 conjugation and deconjugation and found that the Plasmodium parasite consists of both activities. We successfully disrupted the genes individually; however, simultaneously, they were refractory to deletion and essential for parasite survival. Mutants lacking Atg4 and Otu showed normal blood and mosquito stage development. All mice infected with Otu KO sporozoites became patent; however, Atg4 KO sporozoites either failed to establish blood infection or showed delayed patency. Through in vitro and in vivo analysis, we found that Atg4 KO sporozoites invade and normally develop into early liver stages. However, nuclear and organelle differentiation was severely hampered during late stages and failed to mature into hepatic merozoites. We found a higher level of Atg8 in Atg4 KO parasites, and the deconjugation of Atg8 was hampered. We confirmed Otu localization on the apicoplast; however, parasites lacking Otu showed no visible developmental defects. Our data suggest that Atg4 is the primary deconjugating enzyme and that Otu cannot replace its function completely because it cleaves the peptide bond at the N-terminal side of glycine, thereby irreversibly inactivating Atg8 during its recycling. These findings highlight a role for the Atg8 deconjugation pathway in organelle biogenesis and maintenance of the homeostatic cellular balance.


Subject(s)
Cysteine Proteases , Malaria , Parasites , Animals , Mice , Cysteine Proteases/genetics , Cysteine Proteases/metabolism , Parasites/metabolism , Plasmodium berghei , Autophagy-Related Protein 8 Family/genetics , Autophagy-Related Protein 8 Family/metabolism , Autophagy , Protozoan Proteins/metabolism
12.
Med J Armed Forces India ; 79(4): 458-463, 2023.
Article in English | MEDLINE | ID: mdl-37441287

ABSTRACT

Background: Peritoneal dialysis (PD) as a modality of renal replacement therapy (RRT) in acute kidney injury (AKI), continues to be underused. We present our experience with PD in patients with AKI. Method: The data of patients with AKI requiring RRT were retrospectively analyzed. The primary end point was the adequacy of dialysis, and the secondary end point included hemodynamic stability and procedure-related complications. Result: A total of 32 patients with AKI requiring RRT were included in the study. The mean age and the blood pressure at the time of hospitalization were 65.3 ± 6.73 years and 73.7 ± 8.4 mm Hg, respectively. All the patients required vasopressor support; 26 (81%) patients required ventilator support. RRT was initiated at a mean serum creatinine of 6.24 ± 1.17 mg/dL. Rigid stylet catheter was used in 9 (28.2%) and Tenckhoff catheter in 23 (71.8%) patients. The average daily ultrafiltration and weekly Kt/V achieved were 1701 ± 327 mL and 2.19, respectively; these were significantly higher in survivors. After the initiation of PD, hemodynamic instability was observed in 10 (31.2%) patients. The major therapy-related complication noted was PD peritonitis. Conclusions: In a resource-poor environment, PD is an effective modality of RRT for AKI.

13.
Med J Armed Forces India ; 79(4): 392-398, 2023.
Article in English | MEDLINE | ID: mdl-37441297

ABSTRACT

Background: Arthroscopic knee surgeries are commonly performed orthopaedic procedures, which can be done under unilateral spinal anaesthesia (USA) or ultrasound-guided combined sciatic and femoral nerve block (USFB). However, not many studies have compared both these techniques. Hence this study was undertaken to compare USA and USFB in arthroscopic knee surgeries in terms of time to readiness for discharge (TRD). Methods: Eighty patients were randomised into the USA (n = 40) and USFB groups (n = 40). They were administered either USA or USFB on the affected side. The TRD values were compared. Patients were considered fit for discharge after voiding urine, ambulation and obtaining a visual analogue scale (VAS) score of <3. The maximum time required for any of the three parameters was taken as the TRD for that particular patient. Results: The mean TRD was 595.41 ± 195.69 min in the USA group and 351.86 ± 129.51 min in the USFB group (p < 0.001). The median VAS scores for postoperative pain assessment were lower in the USFB group at 2, 4, 12 and 24 h (p < 0.05). The number of patients requiring rescue analgesia was lower in the USFB group at 6 and 12 h after surgery (p < 0.05). Conclusion: Patients undergoing arthroscopic knee surgeries under USFB have an advantage when it comes to TRD as these patients have comparatively better postoperative analgesia, less requirement of rescue analgesia, early voiding of urine and early ambulation.

17.
Indian J Nephrol ; 33(2): 119-124, 2023.
Article in English | MEDLINE | ID: mdl-37234443

ABSTRACT

Introduction: The clinical practice guidelines for peritoneal access state that no particular peritoneal dialysis catheter (PDC) type has been proven superior to another. We present our experience with the use of different PDC tip designs. Method: The study is a retrospective, real-world, observational, outcome analysis correlating the PDC tip design (straight vs. coiled-tip) and technique survival. The primary outcome was technique survival, and the secondary outcome included catheter migration and infectious complications. Result: A total of 50 PDC (28 coiled-tip and 22 straight-tip) were implanted between March 2017 and April 2019 by using a guided percutaneous approach. The 1-month and 1-year technique survival in the coiled-tip PDC was 96.4% and 92.8%, respectively. Of the two coiled-tip catheters lost, one was a consequence of the patient having undergone live related kidney transplantation. The corresponding 1-month and 1-year technique survival with straight-tip PDC was 86.4% and 77.3%, respectively. When compared to straight-tip PDC, the use of coiled-tip PDC was associated with fewer early migration (3.6% vs. 31.8%; odds ratio (OR): 12.6; 95% confidence interval (CI): 1.41-112.39; P = 0.02) and a trend toward favorable 1-year technique survival (P = 0.07; numbers needed to treat = 11). Therapy-related complications noted in the study included peri-catheter leak and PD peritonitis. The PD peritonitis rate in the coiled-tip and straight-tip group was 0.14 and 0.11 events per patient year, respectively. Conclusion: The use of coiled-tip PDC, when placed using a guided percutaneous approach, reduces early catheter migration and shows a trend toward favorable long-term technique survival.

18.
Lancet Reg Health Eur ; 25: 100555, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36818235

ABSTRACT

There are approximately 135 million persons with disabilities in the WHO European Region. In order to address health inequities experienced by this population, Member States and WHO/Europe developed the 'WHO European framework for action to achieve the highest attainable standard of health for persons with disabilities 2022-2030', in close cooperation with organisations of persons with disabilities. The Framework, with its accompanying Resolution, was adopted by all 53 Member States in September 2022. The Framework is aligned with the core priorities of the WHO European Programme of Work 2020-2025, that is, achieving universal health coverage, protecting against health emergencies, and promoting health and well-being. It consists of four objectives, 13 targets, and 20 indicators that act as measures of progress and success, and as drivers for policy action and a roadmap for Member States towards a disability-inclusive health sector. The Framework is expected to have a significant impact on the health and well-being of all in the Region, and especially persons with disabilities, as it will advance inclusive health systems across the Region. Inclusive health sectors will aid towards the achievement of the Sustainable Development Goals, the protection of the human rights of persons with disabilities, and the promotion of their health.

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