Publications by authors named "Ahsan Ausaf Ali"

Cellular mechanical dysregulation can lead to diseases and conditions like tumorigenesis. Drug delivery systems that recognize and respond to specific cellular mechanical characteristics are potentially useful for targeted therapy. We report here the creation of a DNA mechanical nanovehicle that is responsive to cell surface receptor-mediated tensile forces, which can then correspondingly deliver an anticancer drug in situ.

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  • Cell-generated forces play a crucial role in various cellular processes, and measuring these forces is essential for understanding cell behavior in contexts like migration and cancer development, although existing methods are often complex and require specialized skills.
  • A new smartphone-based electrochemical sensor has been developed, utilizing a DNA-based force probe that can detect cellular forces, enabling the measurement of small forces generated by just a few cells, like HeLa cells, through enhanced electrochemical signals.
  • This innovative sensor is portable, cost-effective, and user-friendly, making it a promising complementary tool to existing techniques for detecting cellular forces in biological research.
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  • * These nanodevices can be customized and programmed to act as advanced tools in chemical and cell biology, demonstrating significant biomedical potential.
  • * The review discusses recent advancements in the engineering and application of these DNA nanodevices, along with challenges and future directions for their development.
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Cell-generated forces are a key player in cell biology, especially during cellular shape formation, migration, cancer development, and immune response. A new type of label-free smartphone-based electrochemical DNA sensor is developed here for cellular force measurement. When cells apply tension forces to the DNA sensors, the rapid rupture of DNA duplexes allows multiple redox reporters to reach the electrode and generate highly sensitive electrochemical signals.

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Cells continuously experience and respond to different physical forces that are used to regulate their physiology and functions. Our ability to measure these mechanical cues is essential for understanding the bases of various mechanosensing and mechanotransduction processes. While multiple strategies have been developed to study mechanical forces within two-dimensional (2D) cell culture monolayers, the force measurement at cell-cell junctions in real three-dimensional (3D) cell models is still pretty rare.

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Living systems contain various membraneless organelles that segregate proteins and RNAs via liquid-liquid phase separation. Inspired by nature, many protein-based synthetic compartments have been engineered in vitro and in living cells. Here, we introduce a genetically encoded CAG-repeat RNA tag to reprogram cellular condensate formation and recruit various non-phase-transition RNAs for cellular modulation.

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Living systems contain various functional membraneless organelles that can segregate selective proteins and RNAs via liquid-liquid phase separation. Inspired by nature, many synthetic compartments have been engineered in vitro and in living cells, mostly focused on protein-scaffolded systems. Herein, we introduce a nature-inspired genetically encoded RNA tag to program cellular condensate formations and recruit non-phase-transition target RNAs to achieve functional modulation.

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  • * The study identifies elevated levels of mitochondrial double-stranded RNAs (mt-dsRNAs) in saliva and tears of SS patients and explores their influence on immune responses and glandular function.
  • * Findings suggest that mt-dsRNAs activate the immune system through the JAK1/STAT pathway, contributing to SS pathology and presenting a potential therapeutic target to alleviate autoimmune symptoms.
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The cell membrane is a complex mixture of lipids, proteins, and other components. By forming dynamic lipid domains, different membrane molecules can selectively interact with each other to control cell signaling. Herein, we report several new types of lipid-DNA conjugates, termed as "DNA zippers", which can be used to measure cell membrane dynamic interactions and the formation of lipid domains.

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Hypomethylating agents (HMAs), such as azacitidine and decitabine, induce cancer cell death by demethylating DNAs to promote the expression of tumor-suppressor genes. HMAs also reactivate the transcription of endogenous double-stranded RNAs (dsRNAs) that trigger the innate immune response and subsequent apoptosis via viral mimicry. However, the expression patterns of endogenous dsRNAs and their relevance in the efficacy of HMAs remain largely uninvestigated.

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  • * Their key attributes include programmability, quick membrane integration, and precise assembly, enabling diverse biophysical applications on live cell membranes.
  • * The review highlights recent advancements over the past three years in manipulating these conjugates' biophysical properties, along with current challenges and future research directions in this interdisciplinary area.
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  • The cell membrane consists of various sub-compartments where lipids and proteins interact, but imaging these interactions in real-time is still difficult.
  • The researchers developed a DNA-based probe called "DNA Zipper" that uses fluorescence microscopy to visualize these transient membrane interactions in living cells.
  • By adjusting the DNA probe's length and binding properties, they can increase the duration of lipid interactions and link these findings to T-cell receptor signaling activities.
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Short-lived cell membrane complexes play a key role in regulating cell signaling and communication. Many of these complexes are formed based on low-affinity and transient interactions among various lipids and proteins. New techniques have emerged to study these previously overlooked membrane transient interactions.

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Spiropyrans are a class of photochromic compounds that feature two main isoforms, a closed spiropyran (SP) and an open merocyanine (MC), which are inter-switchable with UV and visible light. The double bond containing MC isomer has several resonance forms with different optical spectra. Consequently, the overall spectral characteristic of the spiropyran solution depends on the relative contribution of each resonance form.

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Background: Long double-stranded RNAs (dsRNAs) are duplex RNAs that can induce immune response when present in mammalian cells. These RNAs are historically associated with viral replication, but recent evidence suggests that human cells naturally encode endogenous dsRNAs that can regulate antiviral machineries in cellular contexts beyond immune response.

Results: In this study, we use photochromic organic compound spiropyran to profile and quantitate dsRNA expression.

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