Functional and Neuropsychological Outcome After Surgical Treatment of Moyamoya Disease

BACKGROUND

Moyamoya disease (MMD) is a rare cerebrovascular disease characterized by progressive stenosis of the supraclinoid internal carotid artery. As a result of chronically decreased brain perfusion, eloquent areas of the brain become hypoperfused, leading to cognitive changes in patients. Repeated infarcts and bleeds produce clinically apparent neurologic deficits.

OBJECTIVES

1) To study the functional and neuropsychological outcome in MMD after revascularization surgery. 2) To find postrevascularization correlation between functional and neuropsychological improvement and radiologic improvement.

METHODS

A single-center prospective and analytic study was carried out including 21 patients with MMD during the study period from March 2021 to December 2022. Patients were evaluated and compared before and after revascularization for functional, neuropsychological, and radiologic status.

RESULTS

Postoperative functional outcome in terms of modified Rankin Scale score showed improvement in 33.33% of cases (P = 0.0769). An overall improving trend was observed in different neuropsychological domains in both adult and pediatric age groups. However, the trend of neuropsychological improvement was better in adults compared with pediatric patients. Radiologic outcome in the form of the Angiographic Outcome Score (AOS) significantly improved after revascularization (P = 0.0001). There was a trend toward improvement in magnetic resonance imaging (MRI) perfusion in the middle cerebral artery and anterior cerebral artery territories, 4.7% (P = 0.075) and 9.33% (P = 0.058) respectively, compared with preoperative MRI perfusion.

CONCLUSIONS

After revascularization, significant improvement occurred in functional and neuropsychological status. This result was also shown radiologically as evidenced by improvement in MRI perfusion and cerebral angiography.

Analysis of Histomorphologic/Molecular Association and Immune Checkpoint Regulators in Epithelioid Glioblastoma and Pleomorphic Xanthoastrocytoma: Are These Tumors Potential Candidates for Immune Checkpoint Blockade?

Accurate diagnosis of Epithelioid glioblastoma (eGB) and pleomorphic xanthoastrocytoma (PXA) is sometimes challenging owing to overlapping histologic and genetic features. There are limited reports on the immune profile of these tumors. In this study, we assessed 21 PXA [15 PXA Grade 2 (PXAG2); 6 PXA Grade 3 (PXAG3)] and 14 eGB for their histopathological and molecular association. Further, their immune profile was compared with GB, IDH1 wild-type (wt) (n-18). Morphologically, PXAG2 mostly differed from eGB; however, it was occasionally difficult to differentiate PXAG3 from eGB due to their epithelioid pattern and less obvious degenerative features. PXAG2 showed predominantly diffuse, whereas variable positivity for epithelial and glial markers was seen in PXAG3 and eGB. All cases showed retained nuclear ATRX and INI-1 . H3K27M or IDH1 mutation was seen in none. P53 mutation was more common in eGB, followed by PXAG3, and least common in PXAG2. BRAF V600E mutation was observed in 66.67% PXAG2, 33.33% PXAG3, and 50% eGB, with 100% concordance between immunohistochemistry (IHC) and sequencing. Thirty-six percent eGB, 33% PXAG3, and 61% PXAG2 harbored CDKN2A homozygous deletion. EGFR amplification was observed in 14% eGB and 66% of GB, IDH wt. PDL1 and CTLA-4 expression was higher in eGB (71.4% and 57.1%), PXAG3 (66.6% and100%), and PXAG2 (60% & 66.7%) as compared with GB, IDH wt (38.8% and 16.7%). Tumor-infiltrating lymphocytes were also observed in a majority of eGB and PXA (90% to 100%) in contrast to GB, IDH wt (66%). This analysis highlights the homogenous molecular and immune profile of eGB and PXA, suggesting the possibility that histologically and molecularly, these two entities represent 2 ends of a continuous spectrum with PXAG3 lying in between. Higher upregulation of PDL1, CTLA-4, and increased tumor infiltrating lymphocytes in these tumors as compared with GB, IDH wt suggests potential candidature for immunotherapy.

Virtual Reality in Preoperative Planning of Complex Cranial Surgery

OBJECTIVE

Changing paradigms of neurosurgical training and limited operative exposure during the residency period have made it necessary to evaluate newer technologies for training. Virtual reality (VR) technology provides three-dimensional reconstruction of routine imaging, along with the ability to see as well as interact. The application of VR technology in operative planning, which is an important part of neurosurgical training, has been incompletely studied so far.

METHODS

Sixteen final-year residents, post-M.Ch. (magister chirurgiae) residents, and fellows were included as study participants. They were divided into 2 groups based on their seniority for further analysis. Five complex cranial cases were selected and a multiple-choice question-based test was prepared by the authors, with 5 questions for each of the cases. The pretest score was determined based on performance on the test after participants accessed routine preoperative imaging. The posttest score was calculated after use of the VR system (ImmersiveTouch VR System, ImmersiveTouch Inc.). Analysis was performed by the investigators, who were blinded to the identity of the participant. Subanalysis based on the type of case and type of question was performed. Feedback was obtained from each participant regarding VR use.

RESULTS

There was an overall improvement in scores from pretest to posttest, which was also noted in the analysis based on the participants' seniority. This improvement was noted to be more for the vascular cases (15.89%) compared with the tumor cases (7.84%). Participants also fared better in questions related to surgical anatomy and surgical approach, compared with questions based on the diagnosis. There was overall positive feedback from participants regarding VR use, and most participants wanted VR to become a routine part of operative planning.

CONCLUSIONS

Our study shows that there is improvement in understanding of surgical aspects after use of this VR system.

Dorsal bony spur in pediatric split cord malformations: eight-year experience from a tertiary care hospital

INTRODUCTION

Dorsal spurs in Type I split cord malformations (SCM-I) are infrequent findings. The pathogenesis of the same is debatable. The objective of this study is to analyze our experience with SCM-I patients having dorsal bony spurs.

METHODOLOGY

Retrospective analysis of SCM patients operated from 2010 to 2017 was performed. Their demographic profile, clinic-radiological features, operative findings, and outcome following surgery were recorded.

RESULTS

Twenty-four cases of Type I SCM harboring dorsal bony spurs were identified with mean age of 4.96 years. The commonest split site was lumbar, documented in 62.5%. Scoliosis was observed in 58.3%. Pre-operative neurological deficits were seen in 66.6% cases with asymmetric weakness of limbs seen in 16.6%. There was no new neurological deficit observed post-operatively.

CONCLUSIONS

This is the largest series of dorsal spurs occurring in SCM, reported in literature so far. Meticulous pre-operative evaluation and imaging are important to identify dorsal spurs for appropriate management and good clinical outcome. Differentiating dorsal spur from ventral spur is important as it has a bearing on surgical approach.

Applications of bioconvection for tiny particles due to two concentric cylinders when role of Lorentz force is significant

The bioconvection flow of tiny fluid conveying the nanoparticles has been investigated between two concentric cylinders. The contribution of Lorenz force is also focused to inspect the bioconvection thermal transport of tiny particles. The tiny particles are assumed to flow between two concentric cylinders of different radii. The first cylinder remains at rest while flow is induced due to second cylinder which rotates with uniform velocity. Furthermore, the movement of tiny particles follows the principle of thermophoresis and Brownian motion as a part of thermal and mass gradient. Similarly, the gyro-tactic microorganisms swim in the nanofluid as a response to the density gradient and constitute bio-convection. The problem is modeled by using the certain laws. The numerical outcomes are computed by using RKF -45 method. The graphical simulations are performed for flow parameters with specific range like 1≤Re≤5, 1≤Ha≤5, 0.5≤Nt≤2.5, 1≤Nb≤3, 0.2≤Sc≤1.8, 0.2≤Pe≤1.0 and 0.2≤Ω≤1.0. It is observed that the flow velocity decreases with the increase in the Hartmann number that signifies the magnetic field. This outcome indicates that the flow velocity can be controlled externally through the magnetic field. Also, the increase in the Schmidt numbers increases the nanoparticle concentration and the motile density.

Gene expression based profiling of pleomorphic xanthoastrocytoma highlights two prognostic subgroups

BACKGROUND

Pleomorphic xanthoastrocytomas (PXAs) are rare, accounting for less than 1% of astrocytomas, and commonly occur in young patients. The majority are WHO grade II. A fraction of tumors that present or recur with malignant change are classified as anaplastic (APXA, grade III). Limited data are available on their molecular characteristics.

METHODOLOGY

Genome-wide expression profiling of 14 PXA and 6 APXAs was performed by microarray. Among differentially expressed genes (DEGs), Cyclin-Dependent Kinase 14 (CDK14) and Mitochondrial Fission Process 1 (MTFP1) were validated by qRT PCR.

RESULT

Unsupervised hierarchical clustering revealed two distinct molecular clusters (Cluster 1: 10 PXA, 3 APXA and Cluster 2: 4 PXA, 3 APXA) with grade II and III tumors distributed in both highlighting molecular heterogeneity within the same grade. There was an insignificant difference in age, sex, immunohistochemical profile, frequency of BRAF mutation, or CDKN2A deletion among the two clusters. Significantly, worse progression-free survival was observed in cluster 2 (P=0.003). mRNA profiling-based prediction of recurrence was superior to and independent of histological grade, BRAF mutation, or CDKN2A deletion status. A total of 10 upregulated and 418 downregulated genes were identified between the PXA clusters. qRT-PCR validation of CDK14 (upregulated in cluster 2) and MTFP1 (upregulated in cluster 1) showed strong concordance with expression array data.

CONCLUSION

This is the first comprehensive study highlighting distinct molecular subgroups of PXA. The differentially expressed genes between two clusters may potentially be used for developing histology independent classification schemes, prognostication and may serve as prospective therapeutic targets for PXA patients.

Comparison of epidural analgesia with ultrasound-guided bilateral erector spinae plane block in aorto-femoral arterial bypass surgery

Objective:

Thoracic Epidural Analgesia (TEA) was compared with ultrasound-guided bilateral erector spinae plane (ESP) block in aorto-femoral arterial bypass surgery for analgesic efficacy, hemodynamic effects, and pulmonary rehabilitation.

Design:

Prospective randomized.

Setting:

Tertiary care centre.

Participants:

Adult patients, who were scheduled for elective aorto-femoral arterial bypass surgery.

Interventions:

It was a prospective pilot study enrolling 20 adult patients who were randomized to group A (ESP block = 10) and group B (TEA = 10). Monitoring of heart rate (HR) and mean arterial pressure (MAP) and pain assessment at rest and deep breathing using visual analog scale (VAS) were done till 48-h post-extubation. Rescue analgesic requirement, Incentive spirometry, oxygenation, duration of ventilation and stay in Intensive Care Unit (ICU) were reported as outcome measures. Statistical analysis was performed using unpaired Student T-test or Mann-Whitney U test. A value of P < 0.05 was considered significant.

Results:

HR was lower in group B than group A at 1 and 2 h post- surgery and at 0.5, 16, 20, and 32 h post-extubation (P < 0.05). MAP were lower in group B than A at 60, 90, 120, 150, 180, 210, 240, 270 minutes and at 0 hour post-surgery and at 4 hours, every 4 hours till 32 hours post-extubation (P < 0.05). Intraoperative midazolam and fentanyl consumption, ventilatory hours, VAS at rest, incentive spirometry, oxygenation, and ICU stay were comparable between the two groups. VAS during deep breathing was more in group A than B at 0.5, 4 hours and every 4 hours till 44 hours post-extubation. The time to receive the first rescue analgesia was shorter in group A than B (P < 0.05).

Conclusion:

Both ESP block and TEA provided comparable analgesia at rest. Further studies with larger sample size are required to evaluate whether ESP block could be an alternative to TEA in aorto-femoral arterial bypass surgery.

Is There Any Relationship Between Systemic Inflammatory Markers And Meningioma Grade?

BACKGROUND

Systemic inflammatory markers have been found to be of value in predicting the prognosis in renal cell and gastrointestinal cancers. Recent studies in gliomas correlating with Systemic inflammatory markers (SIMS) have shown promise in predicting survival.

OBJECTIVE

Meningiomas are the commonest intracranial primary brain tumors in adults. There is a need to distinguish low and high grade meningiomas preoperatively as they have crucial implications for the radicality of surgical excision and prognostication.

METHODS

A retrospective search was conducted, and the newly diagnosed meningioma cases were studied. The preoperative hematological parameters of the patients and pathological tumor grades were noted. The grade 1 meningioma was defined as low-grade meningioma while grade 2 and 3 meningiomas were defined as high-grade meningioma. Statistical analysis was performed to determine the association between the hematological parameters and tumor grade.

RESULTS

Seven hundred and eighty meningioma cases with a mean age of 43.5 years were included. The ANC, NLR, and dNLR were found to be significantly elevated in high-grade meningioma (P = 0.03). Other inflammatory parameters including TLC failed to show a statistically significant difference when compared between the grades of meningioma. ROC analysis further showed limited value of these markers in predicting meningioma grade. However, an elevated ANC (OR = 1.08, 95% CI = 1.02-1.14), male sex (OR = 1.71, 95% CI = 1.13-2.58), and tumor origin from sites other than the skull base or thecal sac (OR = 3.33, 95% CI = 1.93-6.12) were predictive of high-grade meningioma in regression analysis.

CONCLUSION

Preoperative hematological inflammatory parameters have limited value in predicting the grade of tumor in meningiomas. An elevated preoperative ANC, NLR, and dNLR were found to be more frequently associated with high grade of meningiomas.

HLA-E-restricted HIV-1-specific CD8+ T cell responses in natural infection

CD8+ T cell responses restricted by MHC-E, a nonclassical MHC molecule, have been associated with protection in an SIV/rhesus macaque model. The biological relevance of HLA-E-restricted CD8+ T cell responses in HIV infection, however, remains unknown. In this study, CD8+ T cells responding to HIV-1 Gag peptides presented by HLA-E were analyzed. Using in vitro assays, we observed HLA-E-restricted T cell responses to what we believe to be a newly identified subdominant Gag-KL9 as well as a well-described immunodominant Gag-KF11 epitope in T cell lines derived from chronically HIV-infected patients and also primed from healthy donors. Blocking of the HLA-E/KF11 binding by the B7 signal peptide resulted in decreased CD8+ T cell responses. KF11 presented via HLA-E in HIV-infected cells was recognized by antigen-specific CD8+ T cells. Importantly, bulk CD8+ T cells obtained from HIV-infected individuals recognized infected cells via HLA-E presentation. Ex vivo analyses at the epitope level showed a higher responder frequency of HLA-E-restricted responses to KF11 compared with KL9. Taken together, our findings of HLA-E-restricted HIV-specific immune responses offer intriguing and possibly paradigm-shifting insights into factors that contribute to the immunodominance of CD8+ T cell responses in HIV infection.

Turning a New Chapter in Neurosurgery Outpatient Services: Telemedicine A "Savior" in this Pandemic

Background

Teleconsultation services in India, especially in neurosurgery, are relatively new. Despite its large-scale adoption during the COVID-19 pandemic, comprehensive analyses of patients' perspectives and hurdles are lacking.

Materials and Methods

We conducted an anonymized telephonic survey of consecutive neurosurgical patients who availed telemedicine services at our institute, using a validated, structured questionnaire. To prevent bias, interviewers were not involved in the study design/analyses. Patients' perception of usefulness and performance of teleconsultation was graded on a 5-point Likert scale.

Results

Of the 330 patients who availed teleconsultation services, 231 (70%) completed the survey. Even though 91% of the respondents had access to a smartphone, only 10% received a video-based teleconsult. As per respondents, the challenges included poor network (7%), suboptimal communication/discussion (5.6%), lack of physical examination (6%), and misinterpretation of prescription by pharmacists/patients (6%). The majority of the respondents (58%) either agreed/strongly agreed that teleconsultation helped them tide over the medical exigency during the lockdown; however, the clinical diagnosis did not influence this response (P = 0.21). The vast majority of the respondents felt that teleconsultation is beneficial (97%), as it minimizes their exposure to COVID-19. One-third of the patients preferred this service over physical visits and 60% agreed to its continuation till resumption of routine care. Access to video-teleconsultation was the chief suggestion in 39 of 74 suggestions received.

Conclusions

Telemedicine in neurosurgery offers favorable patient satisfaction during this pandemic and may be a satisfactory alternative to physical outpatient services in the future. Video-based teleconsults should be the preferred modality of communication for neurosurgery patients.

Comparison of continuous cardiac output monitoring derived from regional impedance cardiography with continuous thermodilution technique in cardiac surgical patients

Background:

Cardiac output (CO) assessment is a corner stone in advanced haemodynamic management, especially in critical ill patients. The present study was conducted to validate cardiac index and cardiac output by NICaS™ with the thermodilution technique using pulmonary artery catheter in post-operative cardiac surgical patients.

Materials and Methods:

This was a prospective observational clinical study conducted at a tertiary care hospital. 23 adult patients in the age range of 18-65 years who had undergone for elective coronary artery bypass grafting were included in the study.

Results:

Spearman's correlation coefficient of cardiac index between continuous Thermodilution (cTD) and Non-Invasive Cardiac System (NICaS™) showed a good correlation (r = 0.765, 95% confidence interval 0.70 to 0.82, P < 0.0001). There was a good correlation between cTD and NICaS™ for cardiac output (r = 0.759, 95% confidence interval 0.69 to 0.81, P < 0.0001), Bland-Altman plot for cardiac index between cTD and NICaS™ showed a mean bias of −0.66 ± 0.6919 with limits of agreement being −2.02 to 0.6936. Bland-Altman plot for cardiac output between cTD and NICaS™ showed a mean bias of −1.0386 ± 1.17 with limits of agreement being −3.34 to + 1.26. Percentage error for cardiac index and cardiac output were 64.78% and 64% respectively. Polar plot analysis showed an angular bias of 6.32° with radial limits of agreement being −8.114° to 20.75° for cardiac index and angular bias of 5.6682° with radial limits of agreement being −9.1422° to 20.4784° for cardiac output.

Conclusion:

NICaS™ demonstrated a good trending ability for both CI and CO. However, NICaS™ derived parameters are not interchangeable with the values derived from continuous thermodilution technique.

Does Neoadjuvant Chemotherapy Increase the Survival in Patients with Locally Advanced Gastric Cancer Patients? – A Real‑World Evidence

Background: In locally advanced gastric cancer (LAGC), perioperative chemotherapy has shown to improve the survival to a larger extent compared to surgery alone. In India, the treatment followed for gastric carcinoma widely varies based on the type of health-care provider and treatment access. There is a paucity of data on the role of neoadjuvant chemotherapy on survival among LAGC patients in the Indian context. Aim: The aim of this study was to compare the disease-free survival (DFS) and overall survival (OS) between neoadjuvant and adjuvant chemotherapies among LAGC patients. Subjects and Methods: This was a retrospective cohort study involving clinical record review of LAGC patients enrolled between 2015 and 2017 from four tertiary cancer centers in South India. The date for the following events, namely diagnosis, recurrence, death, and last day of visit, was extracted in a mobile-based open-access tool. The median duration of OS and DFS between the neoadjuvant and adjuvant groups was compared using Kaplan–Meier survival curves. Results: Of the 137 patients, 70 (51%) had received neoadjuvant chemotherapy followed by surgery and 67 (49%) had adjuvant chemotherapy following the surgery. The mean (standard deviation) age of participants was 55.4 (11.4) years. Seventy-eight percent of the patients were diagnosed at Stage 3 or 4. Regional lymph nodes were involved in 83.9%. The median duration of follow-up was 15 months. The OS in the neoadjuvant and adjuvant groups was 18.6 months and 8.3 months, respectively. Nonregional lymph node involvement and adjacent organ involvement had independently increased the risk of death. Conclusion: Among LAGC patients, the neoadjuvant chemotherapy indicated a better median and DFS compared to the adjuvant group. However, these findings were statistically not significant. The current study has contributed an important finding to the existing evidences of clinical practice in an Indian setting. Further large-scale studies are required to validate the promising trend of using neoadjuvant chemotherapy in LAGC.

Gamma Knife Radiosurgery: The Gold Standard Treatment for Intracranial Dural Arteriovenous Fistulas without Cortical Venous Drainage

Context

Endovascular therapy is currently the most common treatment approach for intracranial dural arteriovenous fistula (DAVF), followed by microsurgery. Gamma Knife radiosurgery (GKS) is usually reserved as the last modality of treatment of intracranial DAVF.

Aim

To evaluate the clinical and radiological outcome of GKS in the treatment of DAVF without CVD.

Subjects and Methods

This series includes patients who underwent GKS for intracranial DAVF without CVD over 10 years (Jan 2007 to Dec 2016) in All India Institute of Medical Sciences, New Delhi. Their demographic profile, clinical presentation, imaging details, GKS details, and follow-up clinical status were obtained retrospectively. Clinical follow-up, along with radiological assessment using MRI every 6 months was done after GKS. DSA was performed once MRI strongly suggested obliteration of DAVF. Patients who had a clinical follow-up of less than 1 year were excluded from the study.

Results

5 patients (4 males and 1 female) who had DAVF without CVD were included the study. The mean age was 44.8 years. All patients had complete obliteration of fistula on digital subtraction angiography (DSA) at a mean duration of 24 months post GKS. All patients had complete resolution of symptoms at the last follow-up.

Conclusions

Gamma Knife surgery is the most effective and the safest treatment modality for dealing with DAVFs without CVD. Instead of reserving it as the last resort for patients with DAVF without CVD, it should be considered as the gold standard treatment for DAVFs without CVD.

Neglected Traumatic Atlantoaxial Rotatory Dislocation in Adult: A Case Report

Atlantoaxial rotatory dislocations (AARDs) are common in the pediatric population and rarely seen in adults. We describe a case of neglected AARD and subsequent management. A 25-year-old man developed a Fielding type 1 AARD following a road traffic accident. He was managed conservatively for 1.5 months before being referred to us. The patient underwent surgery 1.5 months after the accident. Closed reduction failed and C1-2 fixation with the Harms technique was performed after intraoperative reduction resulting in correction of deformity. Delay of treatment makes intraoperative reduction more difficult and increases the possibility of the chronic permanent change of neck muscles and ligaments. Hence, a high index of suspicion with a thorough clinical examination and judicious use of radiological investigations is paramount to the appropriate management of such cases.

PATH-34. CLINICOPATHOLOGIC, MOLECULAR AND IMMUNOLOGICAL CHARACTERIZATION OF DIFFUSE MIDLINE GLIOMAS: IS THERE A PROGNOSTIC SIGNIFICANCE?

H3K27M Diffuse Midline Gliomas (DMGs) are amongst the most fatal cancers, considered WHO grade IV irrespective of the histological features. Treatment modalities have been ineffective in prolonging survival. The aim was to determine the clinico-pathologic, molecular and immunological characteristics of DMGs in children and adults. Genetic (H3K27M, ATRX, IDH1, p53) and immune (CD3,CD8 and PD-L1) profile of 126 DMGs identified over 10 years was studied with immunohistochemistry (IHC). Sanger sequencing performed for IDH1 and H3K27M mutation. Clinico-radiologic characteristics were reviewed and survival analysis performed. Of the 126 DMGs, 49.2% H3K27M mutant and 50.8% wildtype cases (mean age 21.27 years vs. 36.23 years). 75.68% of pediatric whereas 38.20% of adults were H3K27M mutant. Brainstem (46%) was commonest site in H3K27M mutant pediatric cases while majority of adults (62%) were thalamic. H3K27M was mutually exclusive with IDH mutation in 92.5% cases, whereas p53, ATRX mutation was 56.4% and 30.6% respectively. IHC showed 95% concordance with Sanger sequencing for H3K27M mutation. PD-L1 expression was greater in elderly (>50 years), than young adults and pediatric cases (p=0.002). CD8 expression was greater in adult then pediatric cases (p=0.0001). Overall survival (OS) was not statistically significant in mutant versus wildtype cases in children (p=0.45) as well as adults (p=0.65). Tumor location showed no correlation with OS. Tumor resection independently or on correlation with H3K27M did not influence OS (p=0.505 and p=0.470). Adjuvant therapy impacted survival significantly in adults (p=0.0009) than in pediatric patients (p=0.0669) The study highlights the differences in frequency and location of pediatric and adult H3K27M mutant DMGs. Dismal prognosis in both age groups of H3K27M mutant and wild type DMGs. IHC for H3K27M mutation is an excellent substitute to Sanger sequencing. Our analysis emphasises the role of molecular characterisation for the development of effective therapeutic strategies, for different DMG subgroups.

In vitro expression of vital virulent genes of clinical and environmental isolates of Cryptococcus neoformans/gattii in endothelial cells of human blood-brain barrier

BACKGROUND

Evaluation of the pathogenesis of clinical and environmental cryptococcal isolates to the central nervous system is necessary for understanding the risk. This study was designed to determine the in vitro expression of six important virulent genes of Cryptococcus neoformans/gattii in Human Brain Microvascular Endothelial cells (hBMEC).

METHODS

The hBMEC were infected with Cryptococcus to determine invasion and survival rate at 3, 12 and 24hours by subsequent colony count of internalized yeasts. The whole RNA of the intracellular Cryptococcus was extracted to quantify the expression of CAP10, PLB1, ENA1, URE1, LAC1, and MATα genes by real-time quantitative PCR for 3 and 12hours of infection.

RESULTS

Invasion and survival rates were higher in clinical and standard strains of C. neoformans. A significant difference was observed among the clinical and environmental isolates for the expression of CAP10, ENA1, LAC1, MATα and URE1 at 3hours, and ENA1, LAC1, MATα, PLB1 and URE1 at 12hours. Clinical isolates showed significant upregulation of all the genes except PLB1, which was higher in environmental isolates. Relative expressions at the two time-points showed statistically significant (P=0.043) changes for the clinical isolates and no significance (P=0.063) for environmental isolates.

CONCLUSION

The C. gattii (VGI) isolates showed significantly lower invasion and survival than C. neoformans (VNI, and VNII) irrespective of their sources. Clinical isolates exhibited higher expression for the majority of the virulent genes until 12hours of infection, probably due to their better adaptation in the host system and enhanced pathogenicity than the environmental counterparts.

Comparison of continuous thoracic epidural analgesia with bilateral erector spinae plane block for perioperative pain management in cardiac surgery

Objective:

Continuous thoracic epidural analgesia (TEA) is compared with erector spinae plane (ESP) block for the perioperative pain management in patients undergoing cardiac surgery for the quality of analgesia, incentive spirometry, ventilator duration, and intensive care unit (ICU) duration.

Methodology:

A prospective, randomized comparative clinical study was conducted. A total of 50 patients were enrolled, who were randomized to either Group A: TEA (n = 25) or Group B: ESP block (n = 25). Visual analog scale (VAS) was recorded in both the groups during rest and cough at the various time intervals postextubation. Both the groups were also compared for incentive spirometry, ventilator, and ICU duration. Statistical analysis was performed using the independent Student's t-test. A value of P < 0.05 was considered statistically significant.

Results:

Comparable VAS scores were revealed at 0 h, 3 h, 6 h, and 12 h (P > 0.05) at rest and during cough in both the groups. Group A had a statistically significant VAS score than Group B (P ≤ 0.05) at 24 h, 36 h, and 48 h but mean VAS in either of the Group was ≤4 both at rest and during cough. Incentive spirometry, ventilator, and ICU duration were comparable between the groups.

Conclusion:

ESP block is easy to perform and can serve as a promising alternative to TEA in optimal perioperative pain management in cardiac surgery.

A DNA Vaccine Protects Human Immune Cells against Zika Virus Infection in Humanized Mice

A DNA vaccine encoding prM and E protein has been shown to induce protection against Zika virus (ZIKV) infection in mice and monkeys. However, its effectiveness in humans remains undefined. Moreover, identification of which immune cell types are specifically infected in humans is unclear. We show that human myeloid cells and B cells are primary targets of ZIKV in humanized mice. We also show that a DNA vaccine encoding full length prM and E protein protects humanized mice from ZIKV infection. Following administration of the DNA vaccine, humanized DRAG mice developed antibodies targeting ZIKV as measured by ELISA and neutralization assays. Moreover, following ZIKV challenge, vaccinated animals presented virtually no detectable virus in human cells and in serum, whereas unvaccinated animals displayed robust infection, as measured by qRT-PCR. Our results utilizing humanized mice show potential efficacy for a targeted DNA vaccine against ZIKV in humans.

•

Zika DNA vaccine elicits protective antibody response in humanized DRAG mice.

•

Human myeloid cells and B cells are targets of Zika virus.

A Zika virus vaccine requires testing in human immune cells to determine its effectiveness. In this communication, we report that a DNA vaccine encoding Zika prM and E protein is able to elicit protective neutralizing antibodies against Zika virus in humanized DRAG mice, and that human myeloid cells and B cells are primary targets of Zika virus.

Combination of IL-10 and IL-2 induces oligoclonal human CD4 T cell expansion during xenogeneic and allogeneic GVHD in humanized mice

IL-10 is a crucial anti-inflammatory cytokine which can also exert a seemingly divergent immunostimulatory effects under certain conditions. We found high levels of the cytokine in a xenogeneic GVHD model where NOD-scid IL2rγcnull (NSG) mice were transplanted with human PBMCs in presence of IL-2. Presence of exogenous IL-10 altered the kinetics of IL-2 induced human T cell reconstitution in vivo, showing an initial delay, followed by rapid expansion. Further, compared to IL-2 alone, treatment with IL-2 in combination with IL-10 increased survival in most animals and completely protected ∼20% of mice from GVHD. Additionally, IL-2 induced expansion of both CD4⁺ and CD8⁺ xenoreactive T cells whereas a combination of IL-2 and IL-10 resulted in selective expansion of CD4⁺ T cells only. TCR Vβ repertoire analysis of CD4⁺ T cells showed that in contrast to IL-2 alone, simultaneous presence of both cytokines drastically reduced the Vβ repertoire of the expanded CD4⁺ T cells. Highly restricted Vβ usage was also observed when the cytokine combination was tested in an allogeneic GVHD model where NOD-scid IL2rγc^null mice expressing HLA-DR4 (NSG-DR4) were transplanted with purified CD4⁺ T cells from HLA-DR4 negative donors. Taken together, our results demonstrate that IL-10 can profoundly modulate the subset composition and repertoire of responding T cells during GVHD.

A sliding-bulge structure at the Dicer processing site of pre-miRNAs regulates alternative Dicer processing to generate 5'-isomiRs

5′-isomiRs expand the repertoire of miRNA targets. However, how they are generated is not well understood. Previously, we showed that for some miRNAs in mammalian cells, Drosha cleaves at multiple sites to generate multiple pre-miRNAs that give rise to multiple 5′-isomiRs. Here, we showed that for some other miRNAs, 5′-isomiRs are generated by alternative Dicer processing. In addition, we showed that in miR-203, alternative Dicer processing is regulated by a conserved sliding-bulge structure at the Dicer processing site, which allows the pre-miRNA molecule to fold into two different structures that are processed differently by Dicer. So far no RNA motif that slides to change conformation and alter a protein–RNA interaction has been reported. Thus, our study revealed a novel RNA motif that regulates 5′-isomiR generation in some miRNAs. It might also contribute to regulating protein–RNA interactions in other biological processes, since it takes only one point mutation to generate the sliding bulge, and there are a large number of different RNAs in the cell.

Lentivirus pre-packed with Cas9 protein for safer gene editing

The CRISPR/Cas9 system provides an easy way to edit specific site/s in the genome and thus offers tremendous opportunity for human gene therapy for a wide range of diseases. However, one major concern is off-target effects, particularly with long-term expression of Cas9 nuclease when traditional expression methods such as via plasmid/viral vectors are used. To overcome this limitation, we pre-packaged Cas9 protein (Cas9P LV) in lentiviral particles for transient exposure and showed its effectiveness for gene disruption in cells, including primary T cells expressing specific single guide RNAs (sgRNAs). We then constructed an 'all in one virus' to express sgRNAs in association with pre-packaged Cas9 protein (sgRNA/Cas9P LV). We successfully edited CCR5 in TZM-bl cells by this approach. Using an sgRNA-targeting HIV long terminal repeat, we also were able to disrupt HIV provirus in the J-LAT model of viral latency. Moreover, we also found that pre-packaging Cas9 protein in LV particle reduced off-target editing of chromosome 4:-29134166 locus by CCR5 sgRNA, compared with continued expression from the vector. These results show that sgRNA/Cas9P LV can be used as a safer approach for human gene therapy applications.

Safety profile of the intravenous administration of brain-targeted stable nucleic acid lipid particles

In a clinical setting, where multiple administrations of the therapeutic agent are usually required to improve the therapeutic outcome, it is crucial to assess the immunogenicity of the administered nanoparticles. In this data work, we investigated the safety profile of the repeated intravenous administration of brain-targeted stable nucleic acid lipid particles (RVG-9r-targeted SNALPs). To evaluate local activation of the immune system, we performed analysis of mouse tissue homogenates and sections from cerebellum. To investigate peripheral activation of the immune system, we used serum of mice that were intravenously injected with RVG-9r-targeted SNALPs. These data are related and were discussed in the accompanying research article entitled “Intravenous administration of brain-targeted stable nucleic acid lipid particles alleviates Machado–Joseph disease neurological phenotype” (Conceição et al., in press) [1].

Targeting DNA vaccines to myeloid cells using a small peptide

Targeting DNA vaccines to dendritic cells (DCs) greatly enhances immunity. Although several approaches have been used to target protein Ags to DCs, currently there is no method that targets DNA vaccines directly to DCs. Here, we show that a small peptide derived from the rabies virus glycoprotein fused to protamine residues (RVG-P) can target DNA to myeloid cells, including DCs, which results in enhanced humoral and T-cell responses. DCs targeted with a DNA vaccine encoding the immunodominant vaccinia B8R gene via RVG-P were able to restimulate vaccinia-specific memory T cells in vitro. Importantly, a single i.v. injection of B8R gene bound to RVG-P was able to prime a vaccinia-specific T-cell response that was able to rapidly clear a subsequent vaccinia challenge in mice. Moreover, delivery of DNA in DCs was enough to induce DC maturation and efficient Ag presentation without the need for adjuvants. Finally, immunization of mice with a DNA-vaccine encoding West Nile virus (WNV) prM and E proteins via RVG-P elicited high titers of WNV-neutralizing Abs that protected mice from lethal WNV challenge. Thus, RVG-P provides a reagent to target DNA vaccines to myeloid cells and elicit robust T-cell and humoral immune responses.

Multiplexing seven miRNA-Based shRNAs to suppress HIV replication

Multiplexed miRNA-based shRNAs (shRNA-miRs) could have wide potential to simultaneously suppress multiple genes. Here, we describe a simple strategy to express a large number of shRNA-miRs using minimal flanking sequences from multiple endogenous miRNAs. We found that a sequence of 30 nucleotides flanking the miRNA duplex was sufficient for efficient processing of shRNA-miRs. We inserted multiple shRNAs in tandem, each containing minimal flanking sequence from a different miRNA. Deep sequencing of transfected cells showed accurate processing of individual shRNA-miRs and that their expression did not decrease with the distance from the promoter. Moreover, each shRNA was as functionally competent as its singly expressed counterpart. We used this system to express one shRNA-miR targeting CCR5 and six shRNA-miRs targeting the HIV-1 genome. The lentiviral construct was pseudotyped with HIV-1 envelope to allow transduction of both resting and activated primary CD4 T cells. Unlike one shRNA-miR, the seven shRNA-miR transduced T cells nearly abrogated HIV-1 infection in vitro. Additionally, when PBMCs from HIV-1 seropositive individuals were transduced and transplanted into NOD/SCID/IL-2R γc(-/-) mice (Hu-PBL model) efficient suppression of endogenous HIV-1 replication with restoration of CD4 T cell counts was observed. Thus, our multiplexed shRNA appears to provide a promising gene therapeutic approach for HIV-1 infection.

Characterization of programmed death-1 homologue-1 (PD-1H) expression and function in normal and HIV infected individuals

Chronic immune activation that persists despite anti-retroviral therapy (ART) is the strongest predictor of disease progression in HIV infection. Monocyte/macrophages in HIV-infected individuals are known to spontaneously secrete cytokines, although neither the mechanism nor the molecules involved are known. Here we show that overexpression of the newly described co-stimulatory molecule, PD1 homologue (PD-1H) in human monocyte/macrophages is sufficient to induce spontaneous secretion of multiple cytokines. The process requires signaling via PD-1H as cytokine secretion could be abrogated by deletion of the cytoplasmic domain. Such overexpression of PD-1H, associated with spontaneous cytokine expression is seen in monocytes from chronically HIV-infected individuals and this correlates with immune activation and CD4 depletion, but not viral load. Moreover, antigen presentation by PD-1H-overexpressing monocytes results in enhanced cytokine secretion by HIV-specific T cells. These results suggest that PD-1H might play a crucial role in modulating immune activation and immune response in HIV infection.

Human IL-10 exacerbates graft versus host disease in NOD-scid IL2rγcnull mice transplanted with human PBMCs (TRAN3P.910)

Dysregulated cytokine production plays an important role in the clinical manifestation of acute graft-versus-host disease (aGVHD) following allogeneic bone marrow transplantation (BMT). The role of IL-10, anti-inflammatory cytokine in GVHD pathogenesis remains ambiguous. There are reports showing both beneficial and adverse effects of this cytokine in GVHD progression. Hence to determine the role of IL-10 in GVHD progression, we expressed hIL-10 in NOD-scid IL2rγcnull mice (NSG) by hydrodynamic gene delivery and evaluated its effect on xeogenic GVHD manifestations. We demonstrate that hIL-10 is capable of accelerating the hPBMC induced xeno-GVHD in NSG mice. The marked human T cell infiltration and tissue destruction observed in presence of IL-10 suggest that human IL-10 potently activates and expands pathogenic human T cells with the capacity to induce xeno GVHD. The significant reduction in the number of human cells at the initial phase and robust expansion at later stage suggests that those escapes IL-10 mediated suppression is responsible for the development of xeno-GVHD. Taken together, our results demonstrate for the first time that xenografted human T cells expand in response to IL-10 and mediate tissue damage in xeno GVHD mouse model. These finding provide caution against using rhIL-10 as an immunosuppressive cytokine after allogenic BMT.

Impact of IL-2 and IL-10 on human CD4/CD8 T cell composition and Vβ repertoire in a mouse xenogenic GVHD model (TRAN1P.873)

High level of IL-10 is present in sera of patients with Graft-versus-host disease (GVHD) following allogenic bone marrow transplantation. Our studies with NSG mouse model of GVHD induced by transfer of human PBMCs also revealed high levels of IL-10 in the sera, particularly in presence of IL-2, which accelerates the disease. Blocking antibody to IL-10 was unable to protect the animals from GVHD progression. To directly test the effect of IL-10, GVHD was induced after hydrodynamic injection of plasmids encoding human IL-10 singly or in combination with IL-2. When administered alone, IL-10 treatment resulted in more severe GVHD manifestation. Further, in IL-2 accelerated GVHD, IL-10 was unable to ameliorate the course of the disease. There was a marked difference in the composition of the repopulating human T cells in blood and spleen of mice treated with IL-2 or IL-10 alone compared to a combination of the two cytokines. Singly, both cytokines induced expansion of CD4+ as well as CD8+ T cells with a relatively diverse repertoire but in combination, they induced large oligoclonal expansions of CD4+ T cells with very limited Vβ repertoire and near complete absence of CD8+ T cells. Taken together, our results demonstrate for the first time that IL-10 directly contributes to GVHD pathogenesis. Further, when used in combination with IL-2, IL-10 has a major impact on the repertoire of the responding T cells.

Report of chronic myeloid leukemia in chronic phase from Cancer Institute (Women India Association), Chennai, 2002-2009

Cancer Institute Chennai is the first Institute of Oncological sciences to be established in the country. In ICON meeting, they presented the data of 516 patients, of which 91% patients achieved complete hematological response. The overall survival was 88% and event free survival was 65% at 5 years.

Newer gene editing technologies toward HIV gene therapy

Despite the great success of highly active antiretroviral therapy (HAART) in ameliorating the course of HIV infection, alternative therapeutic approaches are being pursued because of practical problems associated with life-long therapy. The eradication of HIV in the so-called "Berlin patient" who received a bone marrow transplant from a CCR5-negative donor has rekindled interest in genome engineering strategies to achieve the same effect. Precise gene editing within the cells is now a realistic possibility with recent advances in understanding the DNA repair mechanisms, DNA interaction with transcription factors and bacterial defense mechanisms. Within the past few years, four novel technologies have emerged that can be engineered for recognition of specific DNA target sequences to enable site-specific gene editing: Homing Endonuclease, ZFN, TALEN, and CRISPR/Cas9 system. The most recent CRISPR/Cas9 system uses a short stretch of complementary RNA bound to Cas9 nuclease to recognize and cleave target DNA, as opposed to the previous technologies that use DNA binding motifs of either zinc finger proteins or transcription activator-like effector molecules fused to an endonuclease to mediate sequence-specific DNA cleavage. Unlike RNA interference, which requires the continued presence of effector moieties to maintain gene silencing, the newer technologies allow permanent disruption of the targeted gene after a single treatment. Here, we review the applications, limitations and future prospects of novel gene-editing strategies for use as HIV therapy.

In vivo reconstitution of human natural T regulatory cells in NOD/SCID IL2rγcnull mice by expression of human IL-2 (P2174)

Regulatory T cells (TRegs) can suppress a wide range of immune cells, making them an ideal candidate for the treatment graft versus host disease (GVHD). The potential clinical translation of targeted therapy with in vitro expanded human nTRegs is being tested to prevent GVHD, which is a major cause for morbidity and mortality associated with hematopoietic stem cell transplantation. Their usefulness in therapy will depend on their capacity to survive, migrate and retain suppressive activity when introduced into a transplant recipient. The lack of a suitable animal model is a major impediment for investigating the behavior of adoptively transferred nTRegs in vivo. The aim of this study is to develop TRegs reconstituted humanized mice as a preclinical model for understanding their therapeutic usefulness in the transplantation setting. We show that injection of a plasmid encoding human IL-2 is necessary and sufficient for long term engraftment of in vitro expanded nTRegs in NOD-SCID IL2rγcnull mice. Furthermore, the reconstituted TRegs trafficked to different organs of the body and retained their characteristic suppressive function. Finally, in an IL-2 accelerated GVHD model, we show that these in vivo reconstituted TRegs are capable of preventing severe xenogenic response of human PBMCs. Thus, this novel hu-TReg mouse model offers a pre-clinical platform to study the in vivo function and stability of human nTRegs and their ability to modulate autoimmune diseases and GVHD.

Targeted delivery of HMGB1 siRNA to macrophages and dendritic cells for sepsis treatment in humanized mouse model (P6223)

Over expression cytokine by innate immune cells is thought to initiate multiple organ failure in murine models of sepsis. Whether human cytokine storm also plays a similar role is not clear. Here we show that human hematopoietic cells are required to induce sepsis-induced mortality following cecal ligation and puncture (CLP) in the severely immunodeficient NOD/SCID/IL2Rγ-/- mice and siRNA treatment to inhibit HMGB1 release by human macrophages and dendritic cells dramatically reduces sepsis-induced mortality. Following CLP, as compared to immunocompetent WT mice, NOD/SCID/IL2Rγ-/- mice did not show high levels of serum HMGB1 or murine proinflammatory cytokines and were relatively resistant to sepsis-induced mortality. In contrast, NOD/SCID/IL2Rγ-/- mice transplanted with human hematopoietic stem cells (humanized BLT mice) showed high serum levels of HMGB1 as well as multiple human, but not murine proinflammatory cytokines and uniformly succumbed, suggesting human cytokines are sufficient to induce organ failure in this model. Moreover, targeted delivery of HMGB1 siRNA to human macrophages and dendritic cells using a short AchR binding peptide (RVG-9R) effectively suppressed secretion of HMGB1, reduced the human cytokine storm, human lymphocyte apoptosis and rescued humanized mice from CLP-induced mortality. SiRNA treatment was also effective when started after the appearance of sepsis symptoms. These results show that: CLP in humanized mice provides a model to study human sepsis; HMGB1 siRNA might provide a treatment strategy for human sepsis; and RVG-9R provides a tool to deliver siRNA to human macrophages and dendritic cells that could potentially be used suppress a variety of human inflammatory diseases.

Correlates of acute lower respiratory tract infections in children under 5 years of age in India

BACKGROUND

In developing countries, acute lower respiratory tract infections (ALRTI) cause considerable morbidity, hospitalisation and mortality in children aged <5 years.

METHODS

A prospective case-control study was conducted to identify potential socio-demographic, nutritional and environmental risk factors for ALRTI. The World Health Organization definition for ALRTI was used for cases. Healthy children attending child immunisation services were enrolled as controls.

RESULTS

A total of 214 children, 107 cases and 107 controls, were enrolled. Among the cases, pneumonia, severe pneumonia and very severe disease constituted respectively 23.3%, 47.7% and 29%. Among cases and controls, the male-to-female ratio (1.3:1 vs. 0.9:1) and the proportion of infants (64.5% vs. 70.1%) were identical. Parents' literacy level was negatively associated with ALRTI. On multivariate logistic regression analysis, low socio-economic status (OR 4.89, 95%CI 1.93-12.36), upper respiratory infections in family members (OR 5.32, 95%CI 2.11-13.45), inappropriate weaning period (OR 3.01, 95%CI 1.12-8.07), malnutrition (OR 1.75, 95%CI 1.84-3.67), pallor (OR 7.18, 95%CI 2.08-24.82) and cooking fuel other than liquid petroleum gas (OR 3.58, 95%CI 1.23-10.45) were found to be significant risk factors (P < 0.05).

CONCLUSIONS

The present study identified various risk factors for ALRTI, some of which are modifiable by effective community education and public health measures.

Long-term engraftment of human natural T regulatory cells in NOD/SCID IL2rγc(null) mice by expression of human IL-2

Regulatory T cells are essential to maintain immune homeostasis and prevent autoimmunity. Therapy with in vitro expanded human nT_Regs is being tested to prevent graft versus host disease, which is a major cause for morbidity and mortality associated with hematopoietic stem cell transplantation. Their usefulness in therapy will depend on their capacity to survive, migrate appropriately and retain suppressive activity when introduced into a transplant recipient. The lack of a suitable animal model for studying the in vivo reconstitutive capability of human nT_Regs is a major impediment for investigating the behavior of adoptively transferred nT_Regsin vivo. We show that injection of a plasmid encoding human IL-2 is necessary and sufficient for long term engraftment of in vitro expanded nT_Regs in NOD-SCID IL2rγc^null mice. We also demonstrate that these in vivo reconstituted T_Regs traffic to different organs of the body and retain suppressive function. Finally, in an IL-2 accelerated GVHD model, we show that these in vivo reconstituted T_Regs are capable of preventing severe xenogenic response of human PBMCs. Thus, this novel ‘hu-T_Reg mouse’ model offers a pre-clinical platform to study the in vivo function and stability of human nT_Regs and their ability to modulate autoimmune diseases and GVHD.

P-body components LSM1, GW182, DDX3, DDX6 and XRN1 are recruited to WNV replication sites and positively regulate viral replication

In mammalian cells, proteins involved in mRNA silencing and degradation localize to discrete cytoplasmic foci called processing or P-bodies. Here we show that microscopically visible P-bodies are greatly diminished following West Nile viral infection, but the component proteins are not depleted. On the other hand, many P-body components including LSM1, GW182, DDX3, DDX6 and XRN1, but not others like DCP1a and EDC4 are recruited to the viral replication sites, as evidenced by their colocalization at perinuclear region with viral NS3. Kinetic studies suggest that the component proteins are first released from P-bodies in response to WNV infection within 12 h post-infection, followed by recruitment to the viral replication sites by 24-36 h post-infection. Silencing of the recruited proteins individually with siRNA interfered with viral replication to varying extents suggesting that the recruited proteins are required for efficient viral replication. Thus, the P-body proteins might provide novel drug targets for inhibiting viral infection.

Association of indoor air pollution with acute lower respiratory tract infections in children under 5 years of age

BACKGROUND

Indoor air pollution is an important risk factor for acute lower respiratory tract infections (ALRTI) in developing countries.

AIM

To determine the relationship of indoor air pollution with ALRTI in children under 5 years of age.

METHODS

A prospective, case-control study of risk factors, particularly indoor air pollution, for developing ALRTI in children under 5 years of age was conducted in Udupi District Hospital. The WHO definition of ALRTI was used. Healthy children attending immunisation services were enrolled as controls. Data pertaining to important factors causing indoor air pollution such as cooking fuel other than liquid petroleum gas (LPG) and passive smoking were collected along with potential socio-demographic factors and nutrition in both groups and analysed.

RESULTS

A total of 202 children including 101 cases and 101 controls were studied. The proportions of infants (1-12 months) among cases and controls were 62.4% and 71.3%, respectively. Of those with ALRTI, 24.8% had pneumonia, 45.5% had severe pneumonia and 29.7% had very severe disease. Exposure to passive smoking was not associated with ALRTI. Cooking fuel other than LPG was significantly associated with ALRTI (OR 26.3, 95% CI 10.5-65.7). On logistic regression analysis of multiple risk factors, cooking fuel other than LPG emerged as a significant risk factor for developing ALRTI (adjusted OR 4.73, 95% CI 1.67-13.45) along with poor socio-economic status (adjusted OR 3.38, 95% CI 1.63-7.03). Other than LPG, the main fuels used were wood (95%), kerosene and dung and crop residues.

CONCLUSION

Indoor air pollution caused by using cooking fuel other than LPG and socio-economic factors are significantly associated with ALRTI.

Improved siRNA/shRNA functionality by mismatched duplex

siRNA (small interfering RNA) and shRNA (small hairpin RNA) are powerful and commonly used tools in biomedical research. Currently, siRNAs are generally designed as two 21 nt strands of RNA that include a 19 nt completely complementary part and a 2 nt overhang. However, since the si/shRNAs use the endogenous miRNA machinery for gene silencing and the miRNAs are generally 22 nt in length and contain multiple internal mismatches, we tested if the functionality can be increased by designing the si/shRNAs to mimic a miRNA structure. We systematically investigated the effect of single or multiple mismatches introduced in the passenger strand at different positions on siRNA functionality. Mismatches at certain positions could significantly increase the functionality of siRNAs and also, in some cases decreased the unwanted passenger strand functionality. The same strategy could also be used to design shRNAs. Finally, we showed that both si and miRNA structured oligos (siRNA with or without mismatches in the passenger strand) can repress targets in all individual Ago containing cells, suggesting that the Ago proteins do not differentiate between si/miRNA-based structure for silencing activity.

Ago-2-mediated slicer activity is essential for anti-flaviviral efficacy of RNAi

RNA interference can be mediated by fully complementary siRNA or partially complementary miRNA. siRNAs are widely used to suppress viral replication and the fully complementary siRNA bound Ago-2 in the RISC is known to degrade the target RNA. Although other argonaute proteins lacking slicer activity can also bind oligonucleotides with both si and miRNA structures, whether they can also contribute to antiviral effects is not entirely clear. We tested si and miRNA structured oligos for target repression in dual luciferase assays as well as for inhibition of Dengue and West Nile virus replication in ES cells expressing individual Ago proteins. In luciferase assays, both fully complementary and partially complementary oligos effectively repressed their targets in all individual Ago expressing cell lines, although the efficacy with fully complementary oligos was higher in Ago-2+ cells. However, partially complementary oligos had no effect on virus replication in any cell line, while fully complementary siRNAs were highly effective in Ago-2 expressing, but not in cells expressing other Ago proteins. This occurred irrespective of whether the target sequences were located in the coding region or 3'UTR of the virus. We conclude that Ago-2 slicer activity is essential for anti-viral efficacy of siRNAs and miRNA-mediated translational repression/transcript destabilization is too weak to suppress the abundantly expressed flaviviral proteins.

Targeting the HIV entry, assembly and release pathways for anti-HIV gene therapy

Targeting the HIV entry and assembly pathways holds promise for development of novel anti-HIV gene therapy vectors. We characterized discrete dominant negative (DN) Gag and Envelope mutants for their anti-HIV-1 activity. We show here that capsid mutants (Q155N and Y164A) are more potent inhibitors of WT HIV than the matrix mutant 1GA. Both the Envelope mutants tested, V513E and R515A, were equally effective and a combination of Gag and Envelope DN genes significantly enhanced potency. Interestingly, the DN mutants acted at multiple steps in the virus life cycle rather than solely disrupting virus release or infection. Inhibition mediated by R515A could be partially attributed to the Envelope cytoplasmic tail, as deletion of R515A tail partially abrogated its DN effect. Finally, the Y164A/R515A double mutant expressed in a lentiviral vector was effective at inhibiting HIV replication in CD34+ hematopoietic stem cell-derived macrophages, demonstrating the therapeutic potential of our approach.

Anaesthetic management of closed mitral valvotomy for severe mitral stenosis with traumatic kyphoscoliosis

A 42-year-old male patient with rheumatic mitral stenosis was posted for percutaneous transluminal mitral commissurotomy. He had associated traumatic kyphoscoliosis and osteoarthritis of hip and knee joints, causing severe permanent flexion of these joints. This position caused technical difficulty in approach to the femoral vessels. So he was rescheduled for closed mitral valvotomy. This also posed similar problems, but was successfully managed.

Advances in synthetic siRNA delivery

The application of RNA interference-based gene silencing technologies has the potential to treat a variety of illness. Preclinical studies and some early clinical trials have already demonstrated the utility of small interfering RNAs (siRNAs) as a potential novel therapy for the treatment of cancer, viral infections, as well as a wide range of additional diseases. To be effective, an siRNA must be taken up by specific cells, enter the cytoplasm, and be loaded onto the Argonaute protein, the catalytic core of the RNA induced silencing complex (RISC) to direct the cleavage of the homologous transcripts. To meet this need, a variety of novel siRNA delivery strategies have been developed. As our understanding of the molecular mechanisms underlying the RNAi pathway has increased so has the ability to rationally design effective silencing and delivery strategies. This review will examine the latest advances in non-viral delivery of siRNA, with special reference to targeted siRNA delivery to specific target tissues and cell types in vivo in preclinical animal models.

Targeted delivery of siRNA to macrophages for anti-inflammatory treatment

Inflammation mediated by tumor necrosis factor-alpha (TNF-alpha) and the associated neuronal apoptosis characterizes a number of neurologic disorders. Macrophages and microglial cells are believed to be the major source of TNF-alpha in the central nervous system (CNS). Here, we show that suppression of TNF-alpha by targeted delivery of small interfering RNA (siRNA) to macrophage/microglial cells dramatically reduces lipopolysaccharide (LPS)-induced neuroinflammation and neuronal apoptosis in vivo. Because macrophage/microglia express the nicotinic acetylcholine receptor (AchR) on their surface, we used a short AchR-binding peptide derived from the rabies virus glycoprotein (RVG) as a targeting ligand. This peptide was fused to nona-D-arginine residues (RVG-9dR) to enable siRNA binding. RVG-9dR was able to deliver siRNA to induce gene silencing in macrophages and microglia cells from wild type, but not AchR-deficient mice, confirming targeting specificity. Treatment with anti-TNF-alpha siRNA complexed to RVG-9dR achieved efficient silencing of LPS-induced TNF-alpha production by primary macrophages and microglia cells in vitro. Moreover, intravenous injection with RVG-9dR-complexed siRNA in mice reduced the LPS-induced TNF-alpha levels in blood as well as in the brain, leading to a significant reduction in neuronal apoptosis. These results demonstrate that RVG-9dR provides a tool for siRNA delivery to macrophages and microglia and that suppression of TNF-alpha can potentially be used to suppress neuroinflammation in vivo.

RNA interference-based therapeutics for human immunodeficiency virus HIV-1 treatment: synthetic siRNA or vector-based shRNA?

IMPORTANCE OF THE FIELD

Despite the clinical benefits of highly active antiretroviral therapy (HAART), the prospect of life-long antiretroviral treatment poses significant problems, which has spurred interest in developing new drugs and strategies to treat HIV infection and eliminate persistent viral reservoirs. RNAi has emerged as a therapeutic possibility for HIV.

AREAS COVERED IN THIS REVIEW

We discuss progress in overcoming hurdles to translating transient and stable RNAi enabling technologies to clinical application for HIV; covering the past 2 - 3 years.

WHAT THE READER WILL GAIN

HIV inhibition can be achieved by transfection of chemically or enzymatically synthesized siRNAs or by DNA-based vector systems expressing short hairpin RNAs (shRNAs) that are processed intracellularly into siRNA. We compare these approaches, focusing on technical and safety issues that will guide the choice of strategy for clinical use.

TAKE HOME MESSAGE

Introduction of synthetic siRNA into cells or its stable endogenous production using vector-driven shRNA have been shown to suppress HIV replication in vitro and, in some instances, in vivo. Each method has advantages and limitations in terms of ease of delivery, duration of silencing, emergence of escape mutants and potential toxicity. Both appear to have potential as future therapeutics for HIV, once the technical and safety issues of each approach are overcome.

Alternative processing of primary microRNA transcripts by Drosha generates 5' end variation of mature microRNA

BACKGROUND

It is generally believed that the miRNA processing machinery ensures the generation of a mature miRNA with a fixed sequence, particularly at its 5' end. However, we and others have recently noted that the ends of a given mature miRNA are not absolutely fixed, but subject to variation. Neither the significance nor the mechanism behind the generation of such miRNA polymorphism is understood. miR-142 is an abundantly expressed miRNA in hematopoietic cells and exhibits a high frequency of 5' end polymorphism.

METHODOLOGY/PRINCIPAL FINDINGS

Here we show that a shift in the Drosha processing of pri-miRNA generates multiple forms of miR-142s in vivo with differing 5' ends that might target different genes. Sequence analysis of several pre-miRNA ends cloned from T cells reveals that unlike many other pri-miRNAs that are processed into a single pre-miRNA, pri-miR-142 is processed into 3 distinct pre-miR-142s. Dicer processing studies suggest that each of the 3 pre-miR-142s is processed into a distinct double-stranded miRNA, giving rise to 4 mature miRNA variants that might regulate different target gene pools.

CONCLUSIONS/SIGNIFICANCE

Thus, alternative Drosha processing might be a novel mechanism for diversification of the miRNA target gene pool.