shRNA gene silencing Human Islets of langerhans

Isolating RNA from tissues and paraffin-embedded tissue samples can be challenging due to cross-linking of biomolecules and fragmented nucleic acids. The best solution is to slice the tissues into smaller pieces and make a homogenate solution (using tissue homogenizer or grinding liquid nitrogen frozen samples) in presence of RNAse inhibitors. The homogenization process should be carried out on dry ice to maintain the integrity of RNA.

Isolating RNA from tissues and paraffin-embedded tissue samples can be challenging due to cross-linking of biomolecules and fragmented nucleic acids. The best solution is to slice the tissues into smaller pieces and make a homogenate solution (using tissue homogenizer or grinding liquid nitrogen frozen samples) in presence of RNAse inhibitors. The homogenization process should be carried out on dry ice to maintain the integrity of RNA

Isolating RNA from tissues and paraffin-embedded tissue samples can be challenging due to cross-linking of biomolecules and fragmented nucleic acids. The best solution is to slice the tissues into smaller pieces and make a homogenate solution (using tissue homogenizer or grinding liquid nitrogen frozen samples) in presence of RNAse inhibitors. The homogenization process should be carried out on dry ice to maintain the integrity of RNA.

Isolating RNA from tissues and paraffin-embedded tissue samples can be challenging due to cross-linking of biomolecules and fragmented nucleic acids. The best solution is to slice the tissues into smaller pieces and make a homogenate solution (using tissue homogenizer or grinding liquid nitrogen frozen samples) in presence of RNAse inhibitors. The homogenization process should be carried out on dry ice to maintain the integrity of RNA.

Human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) have been greatly used for studies on embryonic development and cell differentiation.iPSCs provide a stable source for either self-renewal or differentiation into suitable cells when cultured in a particular environment. Pluripotent cell culture was originally started by deriving cells from inner cell mass (ICM) from pre-implanted blastocysts, these were called embryonic stem cells. These cells after isolation can be grown on traditional extracellular matrices (like mouse embryonic fibroblasts, MEFs) or feeder-free culture systems. DMEM/F12 has been the most commonly used basal media in the culture of pluripotent cells. These cells are cultured at normal atmospheric oxygen levels, 21%, however, some studies have proposed that 4% oxygen tension may be better for hESC growth. Higher D-glucose concentration (4.2g/l) and osmolarity (320mOsm) that mimics the natural environment of embryonic tissue are optimal for the growth of hESCs. Supplements like N2 and/or B-27, in the presence of growth factors like bFGF, have been shown to increase pluripotency of these cells. bFGF, FGF2 and other ligands of receptor tyrosine kinases like IGF are also required or maintain self-renewal ability of these cells. TGF𝛃1, by its activation of SMAD2/3 signalling, also represses differentiation of iPSCs. Other compounds like ROCK inhibitors reduce blebbing and apoptosis in these cells to maintain their clonogenicity. However, an inhibitor for LIF (leukaemia inhibitory factor, which is one of the pluripotent genes) has an opposing effect. Therefore, it is important to understand the culture conditions and media composition that affect downstream signalling in hESCs or iPSCs that may lead to their differentiation.

Human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) have been greatly used for studies on embryonic development and cell differentiation.iPSCs provide a stable source for either self-renewal or differentiation into suitable cells when cultured in a particular environment. Pluripotent cell culture was originally started by deriving cells from inner cell mass (ICM) from pre-implanted blastocysts, these were called embryonic stem cells. These cells after isolation can be grown on traditional extracellular matrices (like mouse embryonic fibroblasts, MEFs) or feeder-free culture systems. DMEM/F12 has been the most commonly used basal media in the culture of pluripotent cells. These cells are cultured at normal atmospheric oxygen levels, 21%, however, some studies have proposed that 4% oxygen tension may be better for hESC growth. Higher D-glucose concentration (4.2g/l) and osmolarity (320mOsm) that mimics the natural environment of embryonic tissue are optimal for the growth of hESCs. Supplements like N2 and/or B-27, in the presence of growth factors like bFGF, have been shown to increase pluripotency of these cells. bFGF, FGF2 and other ligands of receptor tyrosine kinases like IGF are also required or maintain self-renewal ability of these cells. TGF𝛃1, by its activation of SMAD2/3 signalling, also represses differentiation of iPSCs. Other compounds like ROCK inhibitors reduce blebbing and apoptosis in these cells to maintain their clonogenicity. However, an inhibitor for LIF (leukaemia inhibitory factor, which is one of the pluripotent genes) has an opposing effect. Therefore, it is important to understand the culture conditions and media composition that affect downstream signalling in hESCs or iPSCs that may lead to their differentiation.

Human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) have been greatly used for studies on embryonic development and cell differentiation.iPSCs provide a stable source for either self-renewal or differentiation into suitable cells when cultured in a particular environment. Pluripotent cell culture was originally started by deriving cells from inner cell mass (ICM) from pre-implanted blastocysts, these were called embryonic stem cells. These cells after isolation can be grown on traditional extracellular matrices (like mouse embryonic fibroblasts, MEFs) or feeder-free culture systems. DMEM/F12 has been the most commonly used basal media in the culture of pluripotent cells. These cells are cultured at normal atmospheric oxygen levels, 21%, however, some studies have proposed that 4% oxygen tension may be better for hESC growth. Higher D-glucose concentration (4.2g/l) and osmolarity (320mOsm) that mimics the natural environment of embryonic tissue are optimal for the growth of hESCs. Supplements like N2 and/or B-27, in the presence of growth factors like bFGF, have been shown to increase pluripotency of these cells. bFGF, FGF2 and other ligands of receptor tyrosine kinases like IGF are also required or maintain self-renewal ability of these cells. TGF𝛃1, by its activation of SMAD2/3 signalling, also represses differentiation of iPSCs. Other compounds like ROCK inhibitors reduce blebbing and apoptosis in these cells to maintain their clonogenicity. However, an inhibitor for LIF (leukaemia inhibitory factor, which is one of the pluripotent genes) has an opposing effect. Therefore, it is important to understand the culture conditions and media composition that affect downstream signalling in hESCs or iPSCs that may lead to their differentiation.

Protein isolation is a technique that involves isolation and/ or purification of protein from cells or tissues via chromatography or electrophoresis. The major challenges in protein isolation include: 1. The concentration of proteins in cells is variable and tends to be small for some intracellular proteins. Unlike nucleic acids, proteins cannot be amplified. 2. Proteins are more unstable than nucleic acids. They are easily denatured under suboptimal temperature, pH or salt concentrations. 3. Finally, no generalized technique/protocol can be applied for protein isolation. Proteins may have different electrostatic (number of positively or negatively charged amino acids) or hydrophobic properties. Therefore, protein purification requires multiple steps depending on their charge (a negatively charged resin/column for positively charged proteins and vice-versa), dissolution (using detergents) and unlike in the case of DNA and RNA, instead of using salts, proteins should be isolated by isoelectric precipitation.

TUNEL assay is the cell death detection method where the biochemical marker of apoptosis is DNA fragmentation. The assay involves the microscopical detection of generated DNA fragments with free 3'-hydroxyl residues. in apoptotic cells using enzyme terminal deoxynucleotidyl transferase (TdT) which adds biotinylated nucleotides at the site of DNA breaks. Major challenges of this method involve proper access of the enzyme which could be hampered by poor permeabilization and/or excessive fixation with cross-linking fixative (common with archival tissue). This issue can be resolved by optimizing the incubation time with Proteinase K or CytoninTM.

TUNEL assay is the cell death detection method where the biochemical marker of apoptosis is DNA fragmentation. The assay involves the microscopical detection of generated DNA fragments with free 3'-hydroxyl residues. in apoptotic cells using enzyme terminal deoxynucleotidyl transferase (TdT) which adds biotinylated nucleotides at the site of DNA breaks. Major challenges of this method involve proper access of the enzyme which could be hampered by poor permeabilization and/or excessive fixation with cross-linking fixative (common with archival tissue). This issue can be resolved by optimizing the incubation time with Proteinase K or CytoninTM.