Structure-specific roles for PolG2-DNA complexes in maintenance and replication of mitochondrial DNA.

The homodimeric PolG2 accessory subunit of the mitochondrial DNA polymerase gamma (Pol γ) enhances DNA binding and processive DNA synthesis by the PolG catalytic subunit. PolG2 also directly binds DNA, although the underlying molecular basis and functional significance are unknown. Here, data from Atomic Force Microscopy (AFM) and X-ray structures of PolG2-DNA complexes define dimeric and hexameric PolG2 DNA binding modes. Targeted disruption of PolG2 DNA-binding interfaces impairs processive DNA synthesis without diminishing Pol γ subunit affinities. In addition, a structure-specific DNA-binding role for PolG2 oligomers is supported by X-ray structures and AFM showing that oligomeric PolG2 localizes to DNA crossings and targets forked DNA structures resembling the mitochondrial D-loop. Overall, data indicate that PolG2 DNA binding has both PolG-dependent and -independent functions in mitochondrial DNA replication and maintenance, which provide new insight into molecular defects associated with PolG2 disruption in mitochondrial disease.

PARP1 associates with R-loops to promote their resolution and genome stability.

PARP1 is a DNA-dependent ADP-Ribose transferase with ADP-ribosylation activity that is triggered by DNA breaks and non-B DNA structures to mediate their resolution. PARP1 was also recently identified as a component of the R-loop-associated protein-protein interaction network, suggesting a potential role for PARP1 in resolving this structure. R-loops are three-stranded nucleic acid structures that consist of a RNA-DNA hybrid and a displaced non-template DNA strand. R-loops are involved in crucial physiological processes but can also be a source of genome instability if persistently unresolved. In this study, we demonstrate that PARP1 binds R-loops in vitro and associates with R-loop formation sites in cells which activates its ADP-ribosylation activity. Conversely, PARP1 inhibition or genetic depletion causes an accumulation of unresolved R-loops which promotes genomic instability. Our study reveals that PARP1 is a novel sensor for R-loops and highlights that PARP1 is a suppressor of R-loop-associated genomic instability.

High-speed AFM imaging reveals DNA capture and loop extrusion dynamics by cohesin-NIPBL.

3D chromatin organization plays a critical role in regulating gene expression, DNA replication, recombination, and repair. While initially discovered for its role in sister chromatid cohesion, emerging evidence suggests that the cohesin complex (SMC1, SMC3, RAD21, and SA1/SA2), facilitated by NIPBL, mediates topologically associating domains and chromatin loops through DNA loop extrusion. However, information on how conformational changes of cohesin-NIPBL drive its loading onto DNA, initiation, and growth of DNA loops is still lacking. In this study, high-speed atomic force microscopy imaging reveals that cohesin-NIPBL captures DNA through arm extension, assisted by feet (shorter protrusions), and followed by transfer of DNA to its lower compartment (SMC heads, RAD21, SA1, and NIPBL). While binding at the lower compartment, arm extension leads to the capture of a second DNA segment and the initiation of a DNA loop that is independent of ATP hydrolysis. The feet are likely contributed by the C-terminal domains of SA1 and NIPBL and can transiently bind to DNA to facilitate the loading of the cohesin complex onto DNA. Furthermore, high-speed atomic force microscopy imaging reveals distinct forward and reverse DNA loop extrusion steps by cohesin-NIPBL. These results advance our understanding of cohesin by establishing direct experimental evidence for a multistep DNA-binding mechanism mediated by dynamic protein conformational changes.

Discovery of novel dihydronaphthalene-imidazole ligands as potential inhibitors of Staphylococcus aureus multidrug resistant NorA efflux pump: A combination of experimental and in silico molecular docking studies.

Overexpression of the efflux pump is a predominant mechanism by which bacteria show antimicrobial resistance (AMR) and leads to the global emergence of multidrug resistance (MDR). In this work, the inhibitory potential of library of dihydronapthyl scaffold-based imidazole derivatives having structural resemblances with some known efflux pump inhibitors (EPI) were designed, synthesized and evaluated against efflux pump inhibitor against overexpressing bacterial strains to study the synergistic effect of compounds and antibiotics. Out of 15 compounds, four compounds (Dz-1, Dz-3, Dz-7, and Dz-8) were found to be highly active. DZ-3 modulated the MIC of ciprofloxacin, erythromycin, and tetracycline by 128-fold each against 1199B, XU212 and RN4220 strains of S. aureus respectively. DZ-3 also potentiated tetracycline by 64-fold in E. coli AG100 strain. DZ-7 modulated the MIC of both tetracycline and erythromycin 128-fold each in S. aureus XU212 and S. aureus RN4220 strains. DZ-1 and DZ-8 showed the moderate reduction in MIC of tetracycline in E. coli AG100 only by 16-fold and 8-fold, respectively. DZ-3 was found to be the potential inhibitor of NorA as determined by ethidium bromide efflux inhibition and accumulation studies employing NorA overexpressing strain SA-1199B. DZ-3 displayed EPI activity at non-cytotoxic concentration to human cells and did not possess any antibacterial activity. Furthermore, molecular docking studies of DZ-3 was carried out in order to understand the possible binding sites of DZ-3 with the active site of the protein. These studies indicate that dihydronaphthalene scaffolds could serve as valuable cores for the development of promising EPIs.

Novel lncRNAs LINC01221, RP11-472G21.2 and CRNDE are markers of differential expression in pediatric patients with T cell acute lymphoblastic leukemia.

INTRODUCTION: Pediatric T-cell acute lymphoblastic leukemia (T-ALL) poses significant challenges due to its aggressive nature and resistance to standard treatments. Long non-coding RNAs (lncRNAs) have emerged as potential biomarkers and therapeutic targets in leukemia. This study aims to characterize the lncRNA landscape in pediatric T-ALL, identify specific lncRNAs signatures, and assess their clinical relevance. METHODS: RNA sequencing was performed on T-ALL patient and control samples. Differential expression analysis identified dysregulated lncRNAs and mRNAs. Functional enrichment analysis revealed potential roles of these lncRNAs in cancer pathogenesis. Validation of candidate lncRNAs was conducted using real-time PCR. Clinical correlations were assessed, including associations with patients' clinical characteristics and survival outcomes. RESULTS: Analysis identified 674 dysregulated lncRNAs in pediatric T-ALL, with LINC01221 and CRNDE showing the most interactions in cancer progression pathways. Functional enrichment indicated involvement in apoptosis, survival, proliferation, and metastasis. Top 10 lncRNAs based on adjusted p value < 0.05 and Fold Change > 2 were selected for validation. Seven lncRNAs LINC01221, PCAT18, LINC00977, RP11-620J15.3, RP11-472G21.2, CTD-2291D10.4, and CRNDE showed correlation with RNA sequencing data. RP11-472G21.2 and CTD-2291D10.4 were highly expressed in T-ALL patients, with RP11-620J15.3 correlating significantly with better overall survival (p = 0.0007) at a median follow up of 32 months. The identified lncRNAs were further analysed in B-ALL patients. Distinct lncRNAs signatures were noted, distinguishing T-ALL from B-ALL and healthy controls, with lineage-specific overexpression of LINC01221 (p < 0.0001), RP11-472G21.2 (p < 0.001) and CRNDE (p = 0.04) in T-ALL. CONCLUSION: This study provides insights into the lncRNA landscape of pediatric T-ALL, offering potential diagnostic and prognostic markers. RP11-620J15.3 emerges as a promising prognostic marker, and distinct lncRNAs signatures may aid in the differentiation of T-ALL subtypes. Further research with larger cohorts is warranted to validate these findings and advance personalized treatment strategies for pediatric T-ALL patients.

Visualizing the Path of DNA through Proteins Using DREEM Imaging.

Many cellular functions require the assembly of multiprotein-DNA complexes. A growing area of structural biology aims to characterize these dynamic structures by combining atomic-resolution crystal structures with lower-resolution data from techniques that provide distributions of species, such as small-angle X-ray scattering, electron microscopy, and atomic force microscopy (AFM). A significant limitation in these combinatorial methods is localization of the DNA within the multiprotein complex. Here, we combine AFM with an electrostatic force microscopy (EFM) method to develop an exquisitely sensitive dual-resonance-frequency-enhanced EFM (DREEM) capable of resolving DNA within protein-DNA complexes. Imaging of nucleosomes and DNA mismatch repair complexes demonstrates that DREEM can reveal both the path of the DNA wrapping around histones and the path of DNA as it passes through both single proteins and multiprotein complexes. Finally, DREEM imaging requires only minor modifications of many existing commercial AFMs, making the technique readily available.

TRF2-Mediated Control of Telomere DNA Topology as a Mechanism for Chromosome-End Protection.

The shelterin proteins protect telomeres against activation of the DNA damage checkpoints and recombinational repair. We show here that a dimer of the shelterin subunit TRF2 wraps ∼ 90 bp of DNA through several lysine and arginine residues localized around its homodimerization domain. The expression of a wrapping-deficient TRF2 mutant, named Top-less, alters telomeric DNA topology, decreases the number of terminal loops (t-loops), and triggers the ATM checkpoint, while still protecting telomeres against non-homologous end joining (NHEJ). In Top-less cells, the protection against NHEJ is alleviated if the expression of the TRF2-interacting protein RAP1 is reduced. We conclude that a distinctive topological state of telomeric DNA, controlled by the TRF2-dependent DNA wrapping and linked to t-loop formation, inhibits both ATM activation and NHEJ. The presence of RAP1 at telomeres appears as a backup mechanism to prevent NHEJ when topology-mediated telomere protection is impaired.

Structural and dynamic basis of DNA capture and translocation by mitochondrial Twinkle helicase.

Twinkle is a mitochondrial replicative helicase which can self-load onto and unwind mitochondrial DNA. Nearly 60 mutations on Twinkle have been linked to human mitochondrial diseases. Using cryo-electron microscopy (cryo-EM) and high-speed atomic force microscopy (HS-AFM), we obtained the atomic-resolution structure of a vertebrate Twinkle homolog with DNA and captured in real-time how Twinkle is self-loaded onto DNA. Our data highlight the important role of the non-catalytic N-terminal domain of Twinkle. The N-terminal domain directly contacts the C-terminal helicase domain, and the contact interface is a hotspot for disease-related mutations. Mutations at the interface destabilize Twinkle hexamer and reduce helicase activity. With HS-AFM, we observed that a highly dynamic Twinkle domain, which is likely to be the N-terminal domain, can protrude ∼5 nm to transiently capture nearby DNA and initialize Twinkle loading onto DNA. Moreover, structural analysis and subunit doping experiments suggest that Twinkle hydrolyzes ATP stochastically, which is distinct from related helicases from bacteriophages.

Assembly path dependence of telomeric DNA compaction by TRF1, TIN2, and SA1.

Telomeres, complexes of DNA and proteins, protect ends of linear chromosomes. In humans, the two shelterin proteins TRF1 and TIN2, along with cohesin subunit SA1, were proposed to mediate telomere cohesion. Although the ability of the TRF1-TIN2 and TRF1-SA1 systems to compact telomeric DNA by DNA-DNA bridging has been reported, the function of the full ternary TRF1-TIN2-SA1 system has not been explored in detail. Here, we quantify the compaction of nanochannel-stretched DNA by the ternary system, as well as its constituents, and obtain estimates of the relative impact of its constituents and their interactions. We find that TRF1, TIN2, and SA1 work synergistically to cause a compaction of the DNA substrate, and that maximal compaction occurs if all three proteins are present. By altering the sequence with which DNA substrates are exposed to proteins, we establish that compaction by TRF1 and TIN2 can proceed through binding of TRF1 to DNA, followed by compaction as TIN2 recognizes the previously bound TRF1. We further establish that SA1 alone can also lead to a compaction, and that compaction in a combined system of all three proteins can be understood as an additive effect of TRF1-TIN2 and SA1-based compaction. Atomic force microscopy of intermolecular aggregation confirms that a combination of TRF1, TIN2, and SA1 together drive strong intermolecular aggregation as it would be required during chromosome cohesion.

Densely methylated DNA traps Methyl-CpG-binding domain protein 2 but permits free diffusion by Methyl-CpG-binding domain protein 3.

The methyl-CpG-binding domain 2 and 3 proteins (MBD2 and MBD3) provide structural and DNA-binding function for the Nucleosome Remodeling and Deacetylase (NuRD) complex. The two proteins form distinct NuRD complexes and show different binding affinity and selectivity for methylated DNA. Previous studies have shown that MBD2 binds with high affinity and selectivity for a single methylated CpG dinucleotide while MBD3 does not. However, the NuRD complex functions in regions of the genome that contain many CpG dinucleotides (CpG islands). Therefore, in this work, we investigate the binding and diffusion of MBD2 and MBD3 on more biologically relevant DNA templates that contain a large CpG island or limited CpG sites. Using a combination of single-molecule and biophysical analyses, we show that both MBD2 and MBD3 diffuse freely and rapidly across unmethylated CpG-rich DNA. In contrast, we found methylation of large CpG islands traps MBD2 leading to stable and apparently static binding on the CpG island while MBD3 continues to diffuse freely. In addition, we demonstrate both proteins bend DNA, which is augmented by methylation. Together, these studies support a model in which MBD2-NuRD strongly localizes to and compacts methylated CpG islands while MBD3-NuRD can freely mobilize nucleosomes independent of methylation status.

Limited Effectiveness of Carbonaceous Sorbents in Sequestering Aged Organic Contaminants in Sediments.

Carbonaceous materials are often proposed for use in restoring soils or sediments contaminated with hydrophobic organic contaminants (HOCs). However, the contamination of most sites is a result of historical events, where HOCs have resided in the solid compartment for many years or decades. The prolonged contact time, or aging, leads to reduced contaminant availability and likely diminished effectiveness of using sorbents. In this study, three different carbonaceous sorbents, i.e., biochars, powdered activated carbon, and granular activated carbon, were amended to a Superfund site marine sediment contaminated with DDT residues from decades ago. The amended sediments were incubated in seawater for up to 1 year, and the freely dissolved concentration (Cfree) and the biota-sediment accumulation factors (BSAFs) for a native polychaete (Neanthes arenaceodentata) were measured. Even though the bulk sediment concentrations were very high (6.4-154.9 µg/g OC), both Cfree and BSAFs were very small, ranging from nd to 1.34 ng/L and from nd to 0.024, respectively. The addition of carbonaceous sorbents, even at 2% (w/w), did not consistently lead to reduced DDT bioaccumulation. The limited effectiveness of carbonaceous sorbents was attributed to the low DDT availability due to prolonged aging, highlighting the need for considering contaminant aging when using sorbents for remediation.

Prevalence, Risk Factors, and Impact of Bacterial or Fungal Infections in Acute Liver Failure Patients from India.

BACKGROUND: We evaluated the prevalence, risk factors, and impact of bacterial/fungal infections in acute liver failure (ALF) patients. METHODS: We analyzed clinical, biochemical, and microbiological data of ALF patients with and without bacterial/fungal infections admitted at an institute over the last 5 years. RESULTS: We enrolled 143 patients, 50% males, median age 25 years, with acute viral hepatitis (32.2%), drug-induced injury (18.2%), and tropical illness (14%) as aetiologies of ALF. 110 patients (76.9%) developed bacterial/fungal infections [Bacterial infection: MDR: 70%, PDR: 7%, ESBL: 40%, CRE: 30%, CRAB: 26.6%, MDR-EF: 13.3% and fungal infection: 19 (17.3%)]. On univariable analysis, SIRS (33.6% vs.3%), ICU admission (78.2% vs. 45.5%), mechanical ventilation (88.2% vs. 51.5%), inotropes (39.1% vs. 6.1%), invasive catheters (91.8% vs. 39.4%), and prolonged catheterization (6 days vs. 0 days) were significant risk factors for infections (p < 0.05, each). In contrast, SIRS and catheterization independently predicted infection on multivariable regression. Organ failures [3 (2-4) vs. 1 (0-2)], grade-III-IV HE (67.3% vs. 33.3%), circulatory failure (39.1% vs. 6.1%), coagulopathy (INR > 2.5: 58.2% vs. 33.3%), renal injury (28.2% vs. 6.1%) (p < 0.05), MELD (32.9 ± 8.2 vs. 26.7 ± 8.3) and CPIS [3(2-4) vs. 2(0-2)] were higher in infected vs. non-infected patients (p < 0.001). 30-day survival was significantly lower in infected vs. non-infected patients (17.3% vs. 75.8%, p < 0.001), while no patient survived with fungal infections. Refractory septic shock was the commonest cause of mortality in patients. CONCLUSIONS: Infections due to MDR organisms are high, fungal infections are fatal, and refractory septic shock is the dominant reason for mortality, implying bacterial and fungal infections as the major killer in ALF patients.

TIN2 is an architectural protein that facilitates TRF2-mediated trans- and cis-interactions on telomeric DNA.

The telomere specific shelterin complex, which includes TRF1, TRF2, RAP1, TIN2, TPP1 and POT1, prevents spurious recognition of telomeres as double-strand DNA breaks and regulates telomerase and DNA repair activities at telomeres. TIN2 is a key component of the shelterin complex that directly interacts with TRF1, TRF2 and TPP1. In vivo, the large majority of TRF1 and TRF2 are in complex with TIN2 but without TPP1 and POT1. Since knockdown of TIN2 also removes TRF1 and TRF2 from telomeres, previous cell-based assays only provide information on downstream effects after the loss of TRF1/TRF2 and TIN2. Here, we investigated DNA structures promoted by TRF2-TIN2 using single-molecule imaging platforms, including tracking of compaction of long mouse telomeric DNA using fluorescence imaging, atomic force microscopy (AFM) imaging of protein-DNA structures, and monitoring of DNA-DNA and DNA-RNA bridging using the DNA tightrope assay. These techniques enabled us to uncover previously unknown unique activities of TIN2. TIN2S and TIN2L isoforms facilitate TRF2-mediated telomeric DNA compaction (cis-interactions), dsDNA-dsDNA, dsDNA-ssDNA and dsDNA-ssRNA bridging (trans-interactions). Furthermore, TIN2 facilitates TRF2-mediated T-loop formation. We propose a molecular model in which TIN2 functions as an architectural protein to promote TRF2-mediated trans and cis higher-order nucleic acid structures at telomeres.

Structure, dynamics, and regulation of TRF1-TIN2-mediated trans- and cis-interactions on telomeric DNA.

TIN2 is a core component of the shelterin complex linking double-stranded telomeric DNA-binding proteins (TRF1 and TRF2) and single-strand overhang-binding proteins (TPP1-POT1). In vivo, the large majority of TRF1 and TRF2 exist in complexes containing TIN2 but lacking TPP1/POT1; however, the role of TRF1-TIN2 interactions in mediating interactions with telomeric DNA is unclear. Here, we investigated DNA molecular structures promoted by TRF1-TIN2 interaction using atomic force microscopy (AFM), total internal reflection fluorescence microscopy (TIRFM), and the DNA tightrope assay. We demonstrate that the short (TIN2S) and long (TIN2L) isoforms of TIN2 facilitate TRF1-mediated DNA compaction (cis-interactions) and DNA-DNA bridging (trans-interactions) in a telomeric sequence- and length-dependent manner. On the short telomeric DNA substrate (six TTAGGG repeats), the majority of TRF1-mediated telomeric DNA-DNA bridging events are transient with a lifetime of ~1.95 s. On longer DNA substrates (270 TTAGGG repeats), TIN2 forms multiprotein complexes with TRF1 and stabilizes TRF1-mediated DNA-DNA bridging events that last on the order of minutes. Preincubation of TRF1 with its regulator protein Tankyrase 1 and the cofactor NAD+ significantly reduced TRF1-TIN2 mediated DNA-DNA bridging, whereas TIN2 protected the disassembly of TRF1-TIN2 mediated DNA-DNA bridging upon Tankyrase 1 addition. Furthermore, we showed that TPP1 inhibits TRF1-TIN2L-mediated DNA-DNA bridging. Our study, together with previous findings, supports a molecular model in which protein assemblies at telomeres are heterogeneous with distinct subcomplexes and full shelterin complexes playing distinct roles in telomere protection and elongation.

Cohesin SA1 and SA2 are RNA binding proteins that localize to RNA containing regions on DNA.

Cohesin SA1 (STAG1) and SA2 (STAG2) are key components of the cohesin complex. Previous studies have highlighted the unique contributions by SA1 and SA2 to 3D chromatin organization, DNA replication fork progression, and DNA double-strand break (DSB) repair. Recently, we discovered that cohesin SA1 and SA2 are DNA binding proteins. Given the recently discovered link between SA2 and RNA-mediated biological pathways, we investigated whether or not SA1 and SA2 directly bind to RNA using a combination of bulk biochemical assays and single-molecule techniques, including atomic force microscopy (AFM) and the DNA tightrope assay. We discovered that both SA1 and SA2 bind to various RNA containing substrates, including ssRNA, dsRNA, RNA:DNA hybrids, and R-loops. Importantly, both SA1 and SA2 localize to regions on dsDNA that contain RNA. We directly compared the SA1/SA2 binding and R-loops sites extracted from Chromatin Immunoprecipitation sequencing (ChIP-seq) and DNA-RNA Immunoprecipitation sequencing (DRIP-Seq) data sets, respectively. This analysis revealed that SA1 and SA2 binding sites overlap significantly with R-loops. The majority of R-loop-localized SA1 and SA2 are also sites where other subunits of the cohesin complex bind. These results provide a new direction for future investigation of the diverse biological functions of SA1 and SA2.

Single-molecule level structural dynamics of DNA unwinding by human mitochondrial Twinkle helicase.

Knowledge of the molecular events in mitochondrial DNA (mtDNA) replication is crucial to understanding the origins of human disorders arising from mitochondrial dysfunction. Twinkle helicase is an essential component of mtDNA replication. Here, we employed atomic force microscopy imaging in air and liquids to visualize ring assembly, DNA binding, and unwinding activity of individual Twinkle hexamers at the single-molecule level. We observed that the Twinkle subunits self-assemble into hexamers and higher-order complexes that can switch between open and closed-ring configurations in the absence of DNA. Our analyses helped visualize Twinkle loading onto and unloading from DNA in an open-ringed configuration. They also revealed that closed-ring conformers bind and unwind several hundred base pairs of duplex DNA at an average rate of ∼240 bp/min. We found that the addition of mitochondrial single-stranded (ss) DNA-binding protein both influences the ways Twinkle loads onto defined DNA substrates and stabilizes the unwound ssDNA product, resulting in a ∼5-fold stimulation of the apparent DNA-unwinding rate. Mitochondrial ssDNA-binding protein also increased the estimated translocation processivity from 1750 to >9000 bp before helicase disassociation, suggesting that more than half of the mitochondrial genome could be unwound by Twinkle during a single DNA-binding event. The strategies used in this work provide a new platform to examine Twinkle disease variants and the core mtDNA replication machinery. They also offer an enhanced framework to investigate molecular mechanisms underlying deletion and depletion of the mitochondrial genome as observed in mitochondrial diseases.

Ayme gripp syndrome in an Indian patient.

Ayme Gripp syndrome (OMIM#601088) is a multisystem disorder caused by heterozygous variation in the MAF (OMIM*177075). The typical phenotype comprises a tetralogy of congenital cataract, sensory neural hearing loss, a characteristic facial appearance along with neurodevelopment abnormalities. Exact prevalence estimates are unknown. Only 21 individuals representing 19 families have been reported in the literature till date. To the best of our knowledge, this is the first detailed case report of a boy with Ayme Gripp syndrome from our country. Although he had multiple typical features of the syndrome along with a known pathogenic variation in the MAF, cataract was not observed in him at the age of seven years.

COVID-19 Infection and Arterial Thrombosis: Report of Three Cases.

Thrombotic complications associated with coronavirus disease 2019 (COVID-19) have been described; these have mainly included venous thromboembolic events. Limited literature is available regarding arterial thrombosis. Acute limb ischemia is associated with severe complications that can result in significant morbidity and mortality. Herein, we report 3 cases of COVID-19 infection complicated by arterial thrombosis in the form of acute limb ischemia. Our case series adds to the limited literature regarding arterial thrombosis.

Unprovoked Pulmonary Embolism in Factor VII Deficiency.

Thrombotic events in bleeding disorders such as hemophilia A or B, Von Willebrand disease, afibrinogenemia, factor VII deficiency, and factor XI deficiency are rare but have been reported. These events usually occur in the presence of prothrombotic risk factors such as recent surgery, trauma, or factor replacement therapy. We present a case of a 68-year-old Hispanic female with a history of factor VII deficiency who presented with shortness of breath, chest pain, and palpitations and was found to have pulmonary embolism. Our patient did not have any of the above-mentioned thrombotic risk factors. Our case and review of the literature show that factor VII deficiency does not provide protection against thrombosis.

Ameliorative effects of hempseed (Cannabis sativa) against hypercholesterolemia associated cardiovascular changes.

BACKGROUND AND AIM: Hypercholesterolemia (HC) is a major risk factor for cardiovascular (CV) diseases, that are the major cause of mortality worldwide. Free radicals mediated oxidative stress is a critical player in HC-associated pathophysiological insults including atherosclerosis. Unwanted side effects associated with statins, COX-2 inhibitors, and other synthetic drugs limit their use. Thus, modulation of oxidative stress during HC using green pharmaceuticals seems an appropriate approach against deleterious CV consequences without noticeable side-effect. In this regard, owing to an abundance of proteins, fiber and optimal ratios of omega 6 PUFA: omega-3 PUFA in Hempseed (HS), we aim to exploit its anti-inflammatory and antioxidant properties to ameliorate HC- associated CV effects. METHODS AND RESULTS: Comparing the antioxidant capacity of protein and lipid fractions of HS using ABTS and DPPH assays, HS was supplemented to high-fat diets (HFD) induced hypercholesterolemic wistar rats. After treatment schedules, lipid profiles, histological and ultrastructural investigations, gene and protein expressions of inflammatory markers, markers of oxidative stress were studied and correlated with biophysical parameters such as ECG and impedance/conductance across the aorta. HS demonstrating in vitro free radical scavenging activity, ameliorated the signs of HC as seen with improved lipid profiles, aortic tissue damage and ECG patterns compared to HFD groups. HS administration also relieved the COX-2 mediated inflammation, which correlated well with the improved redox status in the tissue. CONCLUSIONS: Current study evidently demonstrates that the anti-hypercholesterolemic effects of HS are mediated through redox-sensitive modulation of inflammatory pathways.