CBEHx

The figure illustrates how hypoxia-inducible factor 1 (HIF-1) reprogrammes mitochondrial metabolism and maintains mitochondrial quality under low-oxygen conditions. HIF-1 promotes glucose uptake through GLUT transporters and increases glycolytic conversion of glucose to pyruvate, while upregulation of LDHA favours lactate production. Simultaneously, HIF-1-induced PDK inhibits pyruvate dehydrogenase (PDH), limiting the conversion of pyruvate into acetyl-CoA and reducing carbon entry into the tricarboxylic acid (TCA) cycle. Mitochondrial respiration is further adapted through miR-210-mediated suppression of electron transport chain activity and LON-dependent replacement of COX4-1 with the COX4-2 isoform, which supports more efficient oxygen utilisation. HIF-1 also contributes to mitochondrial homeostasis by inducing BNIP3-dependent mitophagy to remove damaged mitochondria and by regulating mitochondrial biogenesis through the c-Myc–PGC-1β pathway. Collectively, these mechanisms shift energy production towards glycolysis, limit oxygen-dependent respiration and reduce cellular stress during hypoxia.

The image provides a detailed comparison between the cellular mechanisms of a healthy neuron and a neuron affected by Parkinson’s disease (PD). In a normal neuron, the genomic DNA (gDNA) within the nucleus is intact and properly organized, while the mitochondria effectively produce energy through the electron transport chain, resulting in sufficient ATP levels for cellular functions. Mitochondrial DNA (mtDNA) is transcribed and translated efficiently, supporting mitochondrial health.

In contrast, a PD neuron shows fragmented gDNA, indicating damage and instability. The mitochondria in PD neurons are compromised, with dysfunctional electron transport chains leading to reduced ATP production. The presence of pro-apoptotic proteins like Bax/Bak contributes to mitochondrial membrane permeability, further exacerbating cellular damage. Additionally, the PD neuron exhibits increased reactive oxygen species (ROS) levels, signifying oxidative stress that damages cellular components. The accumulation of α-synuclein, a protein associated with PD, forms toxic aggregates that disrupt normal mitochondrial and cellular functions, ultimately contributing to the degeneration of neurons in Parkinson’s disease. This comparison underscores the significant cellular disruptions that characterize Parkinson’s disease and highlights the challenges in maintaining neuronal health.

RNA interference (RNAi) is an important cellular mechanism that controls gene expression at the post-transcriptional level. In the microRNA pathway, primary microRNA (pri-miRNA) transcripts are processed in the nucleus by the Drosha complex to generate precursor miRNAs (pre-miRNAs). These precursors are then transported into the cytoplasm by Exportin-5, where Dicer processes them into short, mature miRNA duplexes.

Dicer also processes other double-stranded RNA precursors, including dsRNA and shRNA, to generate small interfering RNAs (siRNAs). The resulting small RNAs are incorporated into the RNA-induced silencing complex (RISC), where an Argonaute (AGO) protein uses the guide RNA to recognise complementary target mRNAs.

The outcome of RNA silencing depends largely on the degree of complementarity between the guide RNA and its target. miRNA-mediated silencing commonly reduces protein production through translational repression and mRNA destabilisation, whereas highly complementary siRNAs can direct AGO-mediated cleavage of the target mRNA. Together, these pathways enable precise regulation of gene expression and contribute to the maintenance of normal cellular function.

The diagram illustrates the key stages of the cell cycle, with a focus on mitosis and cytokinesis. During interphase, the cell grows and replicates its DNA in preparation for division, producing duplicated chromosomes composed of two identical sister chromatids joined at the centromere.

As mitosis begins, the chromosomes condense during prophase, while the mitotic spindle forms and the nuclear envelope breaks down. During metaphase, the duplicated chromosomes align at the cell’s equatorial plane, allowing spindle microtubules to attach and ensure accurate chromosome segregation. In anaphase, the sister chromatids separate and move toward opposite poles of the cell. During telophase, the chromosomes reach the poles and begin to decondense as new nuclear envelopes form around each set.

Finally, cytokinesis divides the cytoplasm and separates the parent cell into two daughter cells that, barring mutations or chromosome-segregation errors, contain essentially identical genetic information.

Transcription relies on complementary base pairing to ensure the accurate transfer of genetic information from DNA to RNA. During this process, the DNA double helix unwinds locally, allowing one strand to serve as the template for RNA synthesis. RNA polymerase incorporates complementary ribonucleotides into the growing RNA molecule, producing a sequence that corresponds precisely to the genetic information encoded within the template strand.

Baby Theo has become the first child from the UK to undergo pioneering surgery for complex gastroschisis while still in the womb, marking a major advance in fetal medicine. Gastroschisis is a rare congenital condition in which a baby’s intestines develop outside the abdominal wall, often leading to serious complications after birth. As part of an international clinical trial, surgeons performed a minimally invasive fetoscopic procedure at 26 weeks’ gestation to reposition the exposed bowel before delivery. Theo was born healthy and discharged from hospital just four days later, raising hopes that prenatal repair could significantly improve outcomes for babies with the most severe forms of the condition and eventually become part of routine clinical practice.

Source: https://www.bbc.co.uk/news/articles/c86ngegz9qno

In the majority of eukaryotes, mitochondria are always inherited in a maternal fashion.

The FDA’s clearance of the first human clinical trial investigating epigenetic reprogramming therapy marks a landmark development in regenerative medicine and translational biotechnology. This pioneering study will evaluate the safety and feasibility of using epigenetic reprogramming to restore cellular function by reversing disease-associated changes in gene regulation without modifying the DNA sequence itself. Although still in its early clinical stages, this milestone represents a critical step toward determining whether epigenetic interventions can be translated into safe and effective therapies for age-related disorders and other chronic diseases, opening new avenues for precision and regenerative medicine.

Antibodies, also known as immunoglobulins (Igs), are glycoproteins produced in response to an immune reaction. They specifically bind to the antigens that triggered the immune response.

Cancer metastasis is a highly complex, multistep biological process responsible for the majority of cancer-related deaths. This illustration depicts the metastatic cascade through the bloodstream, highlighting the critical role of circulating tumour cells (CTCs) in the dissemination of malignant disease.

The process begins when cancer cells undergo epithelial–mesenchymal transition (EMT), acquiring enhanced migratory and invasive properties that enable them to detach from the primary tumour and intravasate into the vascular system. Within the circulation, tumour cells may travel as individual cells or as multicellular clusters, with clustered CTCs often demonstrating greater metastatic potential and resistance to immune surveillance.

As CTCs move through the bloodstream, they are exposed to haemodynamic shear stress and mechanical constraints within the microvasculature. These forces can fragment tumour cell clusters or cause them to become lodged within narrow capillaries. Successful metastatic cells subsequently undergo extravasation, crossing the endothelial barrier into distant tissues where they may enter a dormant state, undergo metabolic reprogramming, evade immune detection, and adapt to the local microenvironment. Under favourable conditions, these disseminated tumour cells can ultimately proliferate and establish secondary tumours.

A deeper understanding of the molecular and cellular mechanisms governing each stage of the metastatic cascade is essential for the development of novel therapeutic strategies aimed at preventing cancer dissemination, improving patient outcomes, and reducing cancer-related mortality.