Publications by authors named "Muhammad Umair Naseem"

Sea anemones are a rich source of peptide toxins spanning a diverse range of biological activities, typically targeting proteins such as ion channels, receptors and transporters. These peptide toxins and their analogues are usually highly stable and selective for their molecular targets, rendering them of interest as molecular tools, insecticides and therapeutics. Recent transcriptomic and proteomic analyses of the sea anemone Aulactinia veratra identified a novel 28-residue peptide, designated Avt1.

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Diverse structural scaffolds have been described in peptides from sea anemones, with the ShKT domain being a common scaffold first identified in ShK toxin from Stichodactyla helianthus. ShK is a potent blocker of voltage-gated potassium channels (K 1.x), and an analog, ShK-186 (dalazatide), has completed Phase 1 clinical trials in plaque psoriasis.

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Sea anemone venoms are complex mixtures of biologically active compounds, including disulfide-rich peptides, some of which have found applications as research tools, and others as therapeutic leads. Our recent transcriptomic and proteomic studies of the Australian sea anemone Telmatactis stephensoni identified a transcript for a peptide designated Tst2. Tst2 is a 38-residue peptide showing sequence similarity to peptide toxins known to interact with a range of ion channels (Na, TRPV1, K and Ca).

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Seven new peptides denominated CboK1 to CboK7 were isolated from the venom of the Mexican scorpion and their primary structures were determined. The molecular weights ranged between 3760.4 Da and 4357.

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Article Synopsis
  • The study investigates the SA8 peptide family in sea anemones, focusing on the genomic structure and evolutionary changes in two species: Actinia tenebrosa and Telmatactis stephensoni.
  • Researchers identified multiple SA8 genes and clusters in both sea anemone species, revealing tissue-specific expression patterns and a unique inverted gene associated with venom.
  • Findings indicate that SA8 is a distinct gene family in Actiniarians that has evolved through structural changes, ultimately being integrated into the venom system of T. stephensoni, although its functional activity remains unclear.
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Myeloid-derived suppressor cells (MDSCs) are key determinants of the immunosuppressive microenvironment in tumors. As ion channels play key roles in the physiology/pathophysiology of immune cells, we aimed at studying the ion channel repertoire in tumor-derived polymorphonuclear (PMN-MDSC) and monocytic (Mo-MDSC) MDSCs. Subcutaneous tumors in mice were induced by the Lewis lung carcinoma cell line (LLC).

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Article Synopsis
  • The Kv1.3 channel is targeted for treating various diseases, and while scorpion venom has blockers, they are hard to obtain in large quantities.
  • The Pichia pastoris expression system offers a cost-effective way to produce these blockers, allowing for sufficient yields of Vm24, AnTx, and Ts6.
  • The study found that tagged and untagged versions of Vm24 and AnTx perform similarly to native toxins in blocking Kv1.3, though untagged Ts6 shows significantly reduced effectiveness, highlighting this method's potential for developing new treatments.
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Upregulation of the voltage-gated potassium channel K1.3 is implicated in a range of autoimmune and neuroinflammatory diseases, including rheumatoid arthritis, psoriasis, multiple sclerosis, and type I diabetes. Understanding the expression, localization, and trafficking of K1.

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The Cm28 in the venom of Centruroides margaritatus is a short peptide consisting of 27 amino acid residues with a mol wt of 2,820 D. Cm28 has <40% similarity with other known α-KTx from scorpions and lacks the typical functional dyad (lysine-tyrosine) required to block KV channels. However, its unique sequence contains the three disulfide-bond traits of the α-KTx scorpion toxin family.

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Doxorubicin (Dox), a widely used anticancer DNA-binding drug, affects chromatin in multiple ways, and these effects contribute to both its efficacy and its dose-limiting side effects, especially cardiotoxicity. Here, we studied the effects of Dox on the chromatin binding of the architectural proteins high mobility group B1 (HMGB1) and the linker histone H1, and the transcription factor retinoic acid receptor (RARα) by fluorescence recovery after photobleaching (FRAP) and fluorescence correlation spectroscopy (FCS) in live cells. At lower doses, Dox increased the binding of HMGB1 to DNA while decreasing the binding of the linker histone H1.

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Margatoxin (MgTx) is a high-affinity blocker of voltage-gated potassium (Kv) channels. It inhibits Kv1.1-Kv1.

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Consensus interferon (cIFN) is a wholly synthetic therapeutic protein which is used to treat hepatitis C/B and certain types of malignancies. It has short serum half-life, therefore, to maintain its therapeutic level in the human body it requires thrice-weekly administration. Various strategies like PEGylation and micro-encapsulation have been developed during the last few years to enhance the pharmacokinetics of small therapeutic peptides.

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