Identification and Characterization of a Novel Palmitoyl Acyltransferase as a Druggable Rheostat of Dynamic Palmitoylome in L. donovani

Palmitoylation has been recently identified as an important post-translational rheostat for controlling protein function in eukaryotes. However, the molecular machinery underlying palmitoylation remains unclear in the neglected tropical parasite, Leishmania donovani. Herein, we have identified a catalog of 20 novel palmitoyl acyltransferases (PATs) and characterized the promastigote-specific PAT (LdPAT4) containing the canonical Asp-His-His-Cys (DHHC) domain. Immunofluorescence analysis using in-house generated LdPAT4-specific antibody demonstrated distinct expression of LdPAT4 in the flagellar pocket of promastigotes. Using metabolic labeling-coupled click chemistry method, the functionality of this recombinant enzyme could be authenticated in E. coli strain expressing LdPAT4-DHHC domain. This was evident by the cellular uptake of palmitic acid analogs, which could be successfully inhibited by 2-BMP, a PAT-specific inhibitor. Using CSS-Palm based in-silico proteomic analysis, we could predict up to 23 palmitoylated sites per protein in the promastigotes, and further identify distinctive palmitoylated protein clusters involved in microtubule assembly, flagella motility and vesicular trafficking. To highlight, proteins such as Flagellar Member proteins (FLAM1, FLAM5), Intraflagellar Transport proteins (IFT88), and flagellar motor assembly proteins including the Dynein family were found to be enriched. Furthermore, analysis of global palmitoylation in promastigotes using Acyl-biotin exchange purification identified a set of S-palmitoylated proteins overlapping with the in-silico proteomics data. The attenuation of palmitoylation using 2-BMP demonstrated several phenotypic alterations in the promastigotes including distorted morphology, reduced motility (flagellar loss or slow flagellar beating), and inefficient invasion of promastigotes to host macrophages. These analyses confirm the essential role of palmitoylation in promastigotes. In summary, the findings suggest that LdPAT4 acts as a functional acyltransferase that can regulate palmitoylation of proteins involved in parasite motility and invasion, thus, can serve as a potential target for designing chemotherapeutics in Visceral Leishmaniasis.

Prevalence and spatial distribution of Ixodid tick populations in the forest fringes of Western Ghats reported with human cases of Kyasanur forest disease and monkey deaths in South India

Kyasanur forest disease (KFD) is a major tick-borne viral haemorrhagic fever caused by KFD virus (KFDV) (Flaviviridae). The disease was reported to be confined to five districts of Karnataka state India until 2011. During 2012-2016, emergence of KFD has been reported in newer areas of Karnataka and adjoining states. Therefore, survey of tick vectors was carried out in these new areas of Karnataka and adjoining states reported with monkey deaths and human cases of KFD. In all selected sites, ticks from the forest floor were collected by lint clothes using flagging method. Tick samples were tested for KFDV nucleic acid by real-time RT-PCR. A total of 4772 ticks, comprising eight species of genus Haemaphysalis and one species each of genus Amblyomma, Ixodes and Rhipicephalus was collected. Haemaphysalis spinigera, the principal vector of KFDV was the predominant tick species (59.5%) collected followed by H. turturis (8.6%). The abundance of H. spinigera ranged from 9.2 to 33.9 per man-hour in the six districts surveyed. Of 214 (4418 tick samples) pools screened by real-time RT-PCR, two pools of H. spinigera were positive for KFDV. High abundance of Haemaphysalis vectors in the six districts indicated that the districts are receptive for KFD outbreaks. KFDV was detected in the tick vectors in the new foci of the KFD. Data on tick distribution will be useful in creating KFD risk map for strengthening the ongoing preventive measures such as vaccination and supply of insect repellents to the high risk groups and intensive health education.

Distribution of therapeutic proteins into thoracic lymph after intravenous administration is protein size-dependent and primarily occurs within the liver and mesentery

Therapeutic proteins can facilitate the targeting and treatment of lymphatic diseases (such as cancer metastases, infections and inflammatory diseases) since they are cleared via the lymphatics following interstitial (SC or IM) administration. However, therapeutic proteins are often administered intravenously (IV). Recently therapeutic proteins have been found to access the thoracic lymph in surprisingly high quantities after IV administration. The aim of this study was to determine, for the first time, the major sites of thoracic lymph access of therapeutic proteins, and the protein properties that enhance lymph access, after IV administration. In order to achieve this, novel methods were developed or optimized to collect hepatic, mesenteric or thoracic lymph from male SD rats. Four different sized PEGylated or non-PEGylated therapeutic proteins (native interferon α2b (IFN, 19kDa), PEGylated interferon α2b (IFN-PEG12, 31kDa), PEGylated interferon α2a (IFN-PEG40, 60kDa) or trastuzumab (150kDa)) were then administered via short IV infusion, and plasma and lymph concentrations of the proteins determined via ELISA. The recovery of the therapeutic proteins in the thoracic lymph duct, which collects lymph from most of the body, was significantly greater for trastuzumab, IFN-PEG40 and IFN-PEG12 (all >3% dose over 8h) when compared to native IFN (0.9% dose). Conversely, the thoracic lymph/plasma (L/P) concentration ratio and thus efficiency of extravasation and transport through the interstitium to lymph was highest for the smaller proteins IFN and IFN-PEG12 (at 90-100% vs 15-30% for trastuzumab and IFN-PEG40). The lower total recovery of IFN and IFN-PEG12 in thoracic lymph reflected more rapid systemic clearance and thus lower systemic exposure. For all therapeutic proteins, the majority (>80%) of lymph access occurred via the hepatic and mesenteric lymphatics. This lymphatic distribution pattern was supported by quantitative imaging of the lymph node distribution of IV administered Cy5 labelled trastuzumab. Optimizing the properties of IV administered therapeutic proteins represents a viable approach to better target and treat pathological states involving the lymphatics, particularly in the liver and mesentery. This includes cancer metastases, infections and inflammatory diseases. Successful development of the novel technique to collect hepatic lymph will also enable future work to evaluate tissue-specific lymph transport in health and disease.

Late posttransplant lymphoproliferative disease: Report of a rare case and role of positron emission tomography-computed tomography

Posttransplant lymphoproliferative disease (PTLD) is an uncommon complication of immunosuppression after solid organ transplantation. Early PTLD (<1 year after transplantation) is frequently found around the allograft, whereas late PTLD (>1 year after transplantation) does not have such a preference. 18-Fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸FDG PET-CT) has clinical significance in the evaluation of PTLD. ¹⁸FDG PET-CT scan allows precise anatomic localization of FDG-avid lesions, hence helpful in staging of disease and evaluation of response to therapy. It can better characterize persistent lesions and differentiate residual tumor from fibrosis or necrosis. We present a rare case report of a perigraft PTLD developing 12 years after renal transplantation sparing the graft, in an Epstein–Barr virus-negative patient.

Transversus Abdominis Plane Block for Inguinal Hernia Repair in a Premature Infant: A Case Report

In this report, we describe the case of a premature infant (36 weeks' postgestational age) who underwent left inguinal hernia repair under general anesthesia without the use of any airway device. Anesthesia was induced and maintained with sevoflurane in oxygen and nitrous oxide. An ultrasound-guided transversus abdominis plane block was performed that provided effective analgesia, obviating the need for opioids in the intraoperative period. The infant's hemodynamics remained stable throughout the surgery. This report also briefly explains the advantages of using a transversus abdominis plane block, compared with neuraxial blockade, for hernia repair surgery.

Evaluation of Metabolic Syndrome and Vitamin D Receptor Gene Polymorphism in Male Factor Infertility

Male factor infertility (MFI) is a growing health issue in society. The vitamin D receptor gene (VDR) is expressed in many tissues and modulates expression of several other genes. The purpose of this study was to investigate the association between MetSyn, VDR gene (FokI, rs-2228570; C > T) polymorphisms and MFI in Indian adults. Fifty cases and fifty-four controls, fulfilling inclusion and exclusion criteria, were included with their informed consent. Fasting plasma glucose, triglyceride, HDL-C were estimated by clinical chemistry analyzer (Beckmam Coulter DXC 800, USA). Serum insulin was measured by electrochemiluminescence immunoassay and VDR gene polymorphism by RFLP-PCR. Statistical analysis was done using SPSS 20.0. MetSyn was more frequent in MFI cases than controls. There was significant difference between waist circumference, fasting plasma glucose, triglycerides in MFI cases and controls. There was significant difference in HOMA-IR between MFI cases and controls (p value < 0.05) and serum insulin was significantly raised in MFI cases (p value < 0.05). VDR gene polymorphism was found to be associated with MFI cases as compared to controls and the serum level of vitamin D was also decreased in MFI cases than in controls (p value < 0.05). This study provides evidence that insulin resistance is more in MFI cases than in controls and occurrence of MetSyn and its components is higher in MFI cases than in controls. Our findings provide evidence that VDR gene (FokI, rs-2228570; C > T) polymorphism increases the risk of male factor infertility.

Postrenal transplant metastatic colonic neoplasm: Posttransplant lymphoproliferative disorder or adenocarcinoma?

Transplant recipients are vulnerable to a horde of infections and neoplastic conditions due to immunosuppression. Posttransplant lymphoproliferative disorder (PTLD) is a condition unique to the transplant recipient occurring due to monoclonal lymphocytic proliferation. It may affect any organ system with reportedly highest incidence in the gastrointestinal tract. The incidence of adenocarcinoma of the colon, however, has not been shown to be uniformly higher in transplant recipients. We report here an unusual case of adenocarcinoma of the ascending colon presenting with liver, lymph node and skin metastasis in a transplant recipient, which simulated PTLD both clinically and radiologically. For any gastrointestinal lesion in transplant recipient, the possibility of carcinoma must be considered. However, a high index of suspicion for PTLD facilitates early diagnosis since the treatment of the two conditions is starkly different.

Renal vein thrombosis as presentation of Non-M3 acute myeloid leukemia in an adult patient

A 46-year-old male presented with left flank pain and was found to have left nephromegaly with renal vein and inferior vena cava (IVC) thrombus. On hematological evaluation, he had leukocytosis and thrombocytopenia. Further evaluation revealed acute myeloid leukemia (AML). Following initial cytoreductive therapy and supportive care for hyperleukocytosis, he underwent left simple nephrectomy with IVC thrombectomy. Postoperatively, he developed massive thrombosis of infrahepatic IVC with renal failure. Renal venous thrombosis as a rare presentation of AML in adults with leukemic hyperleukocytosis has not been reported. In the absence of clear guidelines, early diagnosis and management are desirable.

Simple multiplex RT-PCR for identifying common fusion BCR-ABL transcript types and evaluation of molecular response of the a2b2 and a2b3 transcripts to Imatinib resistance in north Indian chronic myeloid leukemia patients

INTRODUCTION

Chronic myeloid leukemia (CML) is characterized by the Philadelphia chromosome, an abnormally shortened chromosome 22. It is the result of a reciprocal translocation of chromosomes 9 and 22, creating BCR-ABL fusion transcripts, b3a2, b2a2, and e1a2. The aim of our study was to determine the type of BCR-ABL fusion transcripts for molecular diagnosis and investigate the frequency of BCR-ABL fusion transcripts in CML patients by multiplex RT-PCR in CML.

MATERIALS AND METHODS

A single reaction with multiple primers multiplex PCR was used to detect and investigate the type and frequency in 200 CML patients among which 116, 33, and 51 were in CP, AP, and BC phase, respectively.

RESULTS

The study included 200 CML patients, among whom breakpoints in b3a2, b2a2 transcripts were detected in 68% and 24%, respectively, while 8% of the patients showed both b3a2/b2a2. A statistically significant difference was seen between frequency of BCR-ABL fusion transcripts and gender (P = 0.03), molecular response (P = 0.04), and hematological response (P = 0.05). However, there was no correlation found between frequencies of BCR-/ABL fusion transcripts and other clinicopathological parameters like age, type of therapy, thrombocytopenia, and white blood cell count.

CONCLUSION

Multiplex reverse transcriptase-polymerase chain reaction is useful and saves time in the detection of BCR-ABL variants; the occurrence of these transcripts associated with CML can assist in prognosis and treatment of disease.