 |
By Jamshed Arslan Pharm.D.
Microglia are brain's macrophages. In Alzheimer's disease (AD), microglia clear up protein aggregates called amyloid beta plaques. The connection between immune activation and AD is unclear, but a major sensor for danger-signals, called NLRP3 inflammasome, is known to be activated in the brains of patients and transgenic mice (APP/PS1) that overproduce amyloid beta.1 Activated NLRP3 inflammasome leads to the release of pro-inflammatory cytokine (IL-1 beta...
 |
By Christina Towers, PhD.
Cells use the complex process of autophagy to degrade and recycle cytoplasmic material. There are over 20 proteins that have been implicated in this process and appropriately named core autophagy genes (ATGs). Most of these were originally discovered in yeast, arguably the most famous being ATG8. In higher eukaryotes ATG8 evolved into a family of proteins known as the GABA type A receptor-associated protein (GABARAP), which includes the Microtubule Associated Protein 1 light chain 3 (MAP1LC3), better known...
 |
By Jacqueline Carrico, BS, MD Candidate
Chimeric antigen receptor T-cells, better known as CAR-T cells, are being used as a novel anticancer therapy. CAR-T cells are engineered T-cells which express a modified antigen-receptor. Each chimeric antigen receptor contains 3 domains: an extracellular binding domain, a transmembrane hinge domain, and an intracellular activation or costimulatory domain. The extracellular portion is the single chain variable fragment (scFv), made up of an antibody-derived heavy chain and light chain, which ultimately recognize specific tumor antigens. The intracellular activation domain allows T-cell activation upon...
 |
By Jamshed Arslan Pharm.D.
The cell’s oxygen-sensing machinery comprises prolyl-4-hydroxylases (P4Hs 1-3, PHDs 1-3, or EGLN 1-3) and their canonical target hypoxia-inducible factors (HIFs). When oxygen levels are low, PHDs become functionally inactive, leading to HIFs’ stability. PHD1 is thought to provide a link between hypoxia and inflammation, partly because it influences the prototypical proinflammatory transcription factor NF-kB in such a way that suppressing PHD1 reduces inflammation....
 |
By Jamshed Arslan Pharm.D.
von Hippel-Lindau (VHL) disease is associated with tumors arising in multiple organs. Activation of hypoxia-inducible factor (HIF)-alpha underlies the VHL disease pathogenesis. In normoxia, VHL tumor-suppressor protein (pVHL) and E3 ubiquitin ligase lead to proteosomal degradation of HIF-alpha. In hypoxia, HIF-alpha escapes degradation, partly because pVHL binding to HIF-alpha depends on a posttranslational modification (hydroxylation of proline residues) on HIF-alpha that only occurs in normoxia. The exact role of pVHL in tumor hypoxia, when HIF-alpha is stabilized, is poorly...
 |
By Christina Towers, PhD.
The current time from when a discovery is first made on the bench to when that discovery might translate into an approved therapy in cancer patients is an astounding 10-15 years. Scientists and clinicians alike face a daunting uphill battle to find novel targeted therapies that can improve a patient’s outcome yet still maintain minimal adverse side effects. However, recently Dr. Jean Mulcahy Levy, a pediatric neuro-oncologist and physician-scientist, found a way to bypass some of these hurdles. In 2012 she was working as a research-fellow at the University of Colorado in the laboratory of Dr. Andrew Thorburn, an expert in the field of...
 |
By Jamshed Arslan Pharm.D.
Neuromuscular disorders affect the peripheral nervous system and muscles. Spinal muscular atrophy (SMA) is one such incurable disease in which muscles fail to receive signals from the spinal motor neurons (MNs), and consequently, weaken due to inactivity. MN degeneration and muscle atrophy lead to the premature death of the victims. Like most of the neuromuscular disorders, SMA is genetic, and its genetic causes are known: the inactivation of survival motor neuron 1 (SMN1) gene, which reduces the...
 |
By Christina Towers, PhD.
The last 20 years of cancer research have taught us the vast complexities of this life-altering disease. In the last 5 years we have realized that those complexities might extend beyond the cancer cells. The role of the tumor microenvironment (TME) is now front and center in almost every aspect of cancer biology, and autophagy is no exception. The TME consists of a gamut of different cell types that include supporting stroma like fibroblasts and endothelial cells, as well as immune cells. Recent reports have indicated an important role for autophagy in the crosstalk between...
 |
By Christina Towers, PhD.
Misfolded and damaged proteins are degraded by two canonical mechanisms in the cell including the ubiquitin-mediated proteasome system (UPS) and autophagy. Proteins can be targeted for degradation by their N-terminal amino acid which can be modified to become an N-degron. N-degrons allow for selective degradation first through the UPS, however, if the proteasome is not highly functional, these proteins may be degraded via autophagy, a lysosomal mediated form of proteolysis 1. While many studies have shown that...
 |
Induced pluripotent stem cells (iPSCs) may be generated from a wide range of fully differentiated cells, and under optimal conditions may be prompted to differentiate into virtually any fate. Induced stem-like cells not only provide an alternative to embryonic stem cells, but more importantly represent powerful tools for drug development and disease modeling.1
Methods for the induction of pluripotency were developed in 2006, when genes critical for cellular reprograming were identified by Yamanaka and Takahashi, including OCT4, SOX2,...
 |
By Jamshed Arslan Pharm.D.
Multiple myeloma (MM) is a cancer of antibody-producing plasma cells. The bone marrow (BM) of MM patients is hypoxic, and MM cells overexpress many cancerous genes that are regulated by hypoxia-inducible factors (HIFs). Cancer stem cells (CSCs) in the hypoxic BM regions are blamed for the incurability of MM, because CSCs are often resistant to drugs currently used against BM cancers (including proteasome inhibitors and immunomodulatory agents). Dr. Eishi Ashihara at the Kyoto Pharmaceutical University, Japan, and colleagues, set out to characterize the biology of MM stem cells. They found that TGF-beta...
 |
By Yoskaly Lazo-Fernandez, PhD
The field of Cancer Stem Cell (CSC) research has been gaining traction in recent years1. CSCs are a minority group of cells (usually about 1 in 10000) within solid tumors of hematological cancers, which possess similar characteristics to normal stem cells. It is believed that these cells, which are identified by markers usually only found on tissue stem cells, are the only cancerous cells that can induce tumor development and propagation or metastasis2. Consequently, gaining a better understanding of the molecular machinery...
Therapeutic proteins such as monoclonal antibodies (mAbs) can be subject to physical or chemical stress during the manufacturing process and supply chain. A common chemical degradation is the deamidation of the amino acid asparagine to aspartic acid or iso-aspartic acid. Modification of glutamine to glutamic acid is also possible, although this occurs at a slower rate. When deamidation occurs in the antigen binding region of the mAb, it can result in a loss of potency. This sequence liability may be defined as a critical quality attribute and represents a risk to the development of novel biologics and biosimilars alike. As such, it is important to have reliable protein characterization methods with sufficient sensitivity and selectivity to identify and quantify levels of deamidation.
The transformation of an amide side-chain, via a succinimide intermediate, to a carboxylic acid results in a change in the net charge of the...
 |
By Jamshed Arslan Pharm.D.
Parkin got its name from Parkinson’s disease (PD). Being an E3 ubiquitin ligase enables Parkin to ubiquitinate and degrade proteins involved in PD (such as CDCrel-1, α-synuclein, and synphilin-1). Now we know that mutations in the Parkin gene (PARK2) can not only lead to a hereditary form of PD, but may also make people prone to various malignancies including breast cancer. Hypoxia-inducible factor-1α (HIF-1α), which adapts cells to hypoxic conditions in...
 |
By Jamshed Arslan Pharm.D.
Interneurons transmit impulses between other neurons, in part, to facilitate the birth of neurons. Cortical interneurons themselves arise from the progenitors in the ventral telencephalon, a brain region that generates basal ganglia. The role of mechanistic target of rapamycin (MTOR) signaling in this process is poorly understood, even though MTOR is known to determine brain size. By deleting Mtor in mouse interneuron progenitors and their progeny, Dr. Woo-Yang Kim’s team at the University of Nebraska Medical Center, USA, found two homeostatic activities of MTOR in the developing brain: regulation of autophagy and...
 |
By Christina Towers, PhD.
The degradation of cellular proteins is a critical step of both regulation and quality control and results in the turn over and recycling of critical amino acids. The two main mechanisms of protein degradation converge on either the proteasome or the lysosome, the latter of which can be further subdivided into macroautophagy, microautophagy, and chaperone mediated autophagy.
Macroautophagy is the...
 |
By Yoskaly Lazo-Fernandez, PhD
The first description of what is called today an autophagosome was given in a paper published in 1957. Its author employed electron microscopy to observe the neonatal features of mouse kidneys1. Autophagosomes where then described as large round bodies found in the cytoplasm, primarily of proximal tubule epithelial cells, and consisting of an amorphous material containing concentrically lamellar structures and mitochondria. It was not by chance that these structures were found in kidney tubules, because autophagy plays an essential role in kidney function both in health and disease2,3. This blog will briefly introduce the main...
 |
By Christina Towers, PhD.
The fundamental process that cells use to degrade damaged cytoplasmic material and recycle nutrients is called autophagy. This term was first coined by the Belgium biochemist Christian de Duve stemming from the Greek translations of “auto” meaning “self” and “phagy” meaning “eat”, thus: “autophagy” translates to “eating one’s self”. de Duve’s seminal work identified the previously unknown organelle, the lysosome and transpired in a Nobel Prize in Medicine in 19741.
Almost 4 decades after de Duve...
 |
By Jamshed Arslan Pharm.D.
Muscle atrophy is a common feature of many tumors. Cancer-induced muscle wasting, or cancer cachexia, results from pro-inflammatory cytokines (TNFα and IL-6) and/or agonists of type IIB activin receptors (ActRIIB), but the key humoral factors have remained elusive. Animal studies have implicated systemic inflammation-induced activation of p38β MAPK-C/EBPβ signaling, but the etiology of cancer cachexia was unclear until recently. A team led by researchers at the University of...
 |
By Jamshed Arslan Pharm.D.
Cancers of nerve, adipose, and other soft tissues are called soft tissue sarcomas (STS). Malignant peripheral nerve sheath tumor (MPNST) is an example of a rare and hard-to-treat STS; even after the surgical removal (which is the only viable option), the tumor often relapses causing poor patient survival. The search for novel treatment targets led a team of researchers in Japan [1] to a transcription factor called hypoxia-inducible factor (HIF). Normally, HIF-1α adapts cells to hypoxic conditions by localizing to the nucleus where it regulates cell growth with the help of transcriptional co-activators...
 |
By Yoskaly Lazo-Fernandez, PhD
The cell surface receptor CD95 (also known as Fas or APO-1) is the best-characterized member of the tumor necrosis factor (TNF) receptor superfamily1. Many receptors in this family, including CD95 are called Death Receptors because of their ability to induce apoptosis2. In cells expressing CD95, apoptosis is triggered by the binding of this receptor’s specific ligand, CD95L. This mechanism, which was originally discovered in the early nineties, allows CD95L...
 |
By Jamshed Arslan Pharm.D.
Triple-negative breast cancer (TNBC) is difficult to treat because it does not express the receptors (estrogen, progesterone, and HER2) against which effective therapies are available. TNBC defeats the body’s regulation on unchecked growth, but its winning strategy remained unclear until recently. A research team, led by Dr. William Kaelin at the Dana-Farber Cancer Institute in Boston, recently discovered that TNBC cells release glutamate to disable a cancer-stunting enzyme, EglN1. This enzyme targets the...
By Christina Towers, PhD.
It has long been known that programmed cell death can take place in many forms. The most well characterized form, apoptosis, occurs when either extrinsic or intrinsic stimuli stimulate signaling cascades that result in a series of caspase cleavage events resulting in cleavage and activation of the effector caspase-3. The end result is cell shrinkage, condensation and cleavage of chromosomal DNA, and plasma membrane blebbing that leaves the cell membrane intact1. Apoptotic cells are engulfed by antigen presenting cells and induce anti-inflammatory and tolerogenic immune responses2. Alternatively, necroptosis, a programmed form of necrosis, is less characterized. However, it is now known that this process is also tightly regulated and mediated by a complex...
By Yoskaly Lazo-Fernandez, PhD
Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, is a progressive neurological disease that affects the motor neuron system and thus voluntary control of muscle movement. This disease belongs to a broader group of disorders known as motor neuron diseases, characterized by progressive degeneration and death of motor neurons. There are two types of motor neurons, including upper- and lower-motor neurons, based on the position of their somas within the CNS. Upper motor neuron somas are located in the motor cortex and their axons descend to the spinal cord where they activate the lower motor neurons. Lower motor neurons have somas within the spinal cord and extend their axons peripherally to innervate skeletal muscles. In ALS patients...
By Christina Towers, PhD
Autophagy is an important cellular process that facilitates the degradation of damaged cytoplasmic material and toxic protein aggregates. Its role in neuronal function is apparent by the neurodegenerative phenotypes observed in autophagy deficient genetic mouse models. Mice with neuron-specific knock out of the core autophagy protein, ATG7, are viable but most go on to develop behavioral defects and eventually massive neuronal loss in the cerebral corticies1.
But perhaps the most causative links between autophagy and neurological functioning have been observed in animal models of progressive neurodegenerative diseases including Alzheimer’s, Parkinson’s, and Huntington’s disease. Each of these devastating diseases is characterized by a build-up of toxic protein aggregates: β-...
