Biology

A protein known as ALKBH7 plays a key role in controlling the programmed necrosis pathway. To determine the location of ALKBH7 in cells, MIT researchers engineered these cells to express ALKBH7. The cells appear yellow where ALKBH7 is present in the mitochondria. Credit: Jennifer Jordan and Dragony Fu

MIT researchers have identified a protein, ALKBH7, that is crucial to a cell death process known as programmed necrosis. When cells suffer unrepairable DNA damage, the programmed necrosis pathway is initiated so that the cells rupture and die. This prevents the damaged cells from potentially developing into cancer cells. Cancer cells are sometimes resistant to another type of programmed cell death known as apoptosis.

According to researcher Leona Samson, "People really used to think of necrosis as cells just falling apart, that it wasn't programmed and didn't require gene products to make it happen. In the last few years it has become more clear that this is an active process that requires proteins to take place." These findings could mean potential new targets for cancer drug treatments. The drugs could work in a similar manner to the necrosis protein ALKBH7 to cause cancer cells to self destruct.

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• Study IDs Key Protein for Cell Death (Science Daily)

This is a colony of human embryonic stem cells (ESCs) (upper portion) generated by somatic cell nuclear transfer (SCNT). Credit: Cell, Tachibana et al.

For the first time, researchers have successfully produced human embryonic stem cells using a technique called somatic cell nuclear transfer (SCNT). This process involves removing the nucleus from an egg cell and replacing it with the nucleus of another cell. In the study, human skin cell nuclei were transplanted into unfertilized enucleated (removed genetic material) egg cells. These cells went on to develop and produce embryonic stem cells. The stem cells had no chromosomal abnormalities and normal gene function.

According to researcher Shoukhrat Mitalipov, "A thorough examination of the stem cells derived through this technique demonstrated their ability to convert just like normal embryonic stem cells, into several different cell types, including nerve cells, liver cells and heart cells. Furthermore, because these reprogrammed cells can be generated with nuclear genetic material from a patient, there is no concern of transplant rejection." Stem cell therapies could be used to treat individuals with conditions such as multiple sclerosis, spinal cord injuries, cardiac disease, and Parkinson's disease.

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• Human Skin Cells Converted Into Embryonic Stem Cells (Science Daily)

Mosquito Credit: James Gathany / CDC

Can bacteria prevent the spread of malaria? Michigan State University researchers have shown that the bacteria Wolbachia can actually prevent the transmission of malaria to humans by protecting mosquitoes from the malaria parasite. The researchers developed a strain of mosquitoes that were infected with Wolbachia bacteria. These mosquitoes transmitted the bacteria to the entire mosquito population providing protection against the malaria parasite.

According to researcher Zhiyong Xi, "Our work is the first to demonstrate Wolbachia can be stably established in a key malaria vector, the mosquito species Anopheles stephensi, which opens the door to use Wolbachia for malaria control." Once the mosquitoes gain immunity to the malaria parasite, they do not transmit malaria to humans.

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• Using Bacteria to Stop Malaria (Science Daily)

Image Credit: Samarttiw / FreeDigitalPhotos.net

University of Edinburgh researchers have uncovered evidence that indicates that exposure to the sun's ultraviolet rays has health benefits. When a person's skin is exposed to the sun's rays, it reduces blood pressure by causing levels of nitric oxide to rise in the blood. This dramatic reduction in blood pressure could cut the risks of developing heart disease or stroke.

According to researcher Richard Weller, "We suspect that the benefits to heart health of sunlight will outweigh the risk of skin cancer. The work we have done provides a mechanism that might account for this, and also explains why dietary vitamin D supplements alone will not be able to compensate for lack of sunlight." While blood pressure dropped for individuals in the study who were exposed to UV rays for specific time periods, vitamin D levels remained unaffected.

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• Sunshine Could Benefit Health and Prolong Life (Science Daily)

A healthy Streptococcus pneumoniae bacterial cell (upper left) next to a bacterial cell destroyed and lysed by the human milk protein complex HAMLET (lower right). Credit: Laura R. Marks

A protein complex found in human breast milk has been shown to make antibiotic-resistant bacteria sensitive to several classes of antibiotics. University at Buffalo researchers have discovered that the protein complex known as Human Alpha-lactalbumin Made Lethal to Tumor Cells (HAMLET) can reverse antibiotic resistance in bacteria such as penicillin-resistant Streptococcus pneumoniae and methicillin-resistant Staphylococcus aureus (MRSA).

According to lead researcher Anders Hakansson, "HAMLET has the potential to minimize the concentrations of antibiotics we need to use to fight infections, and enable us to use well-established antibiotics against resistant strains again." The researchers state that bacteria have trouble developing resistance to HAMLET. Exposing bacteria to HAMLET allowed the researchers to lower the dose of antibiotics needed to destroy these bacteria. HAMLET is not only deadly to some bacteria, but also makes resistant bacteria vulnerable to antibiotics.

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• Protein Complex Found in Human Breast Milk Can Help Reverse Antibiotic Resistance in Superbugs (Science Daily)

Image: Dream Designs / FreeDigitalPhotos.net

Researchers have discovered a link between obesity and cellular changes in the brain. These changes take place in the neurons of the hypothalamus. The hypothalamus directs a multitude of important functions in the body, including the regulation of food and water intake. Certain receptors in the hypothalamus have been found to either promote or inhibit the release of an appetite stimulant called orexin A. The study found that stimulated receptors in normal weight mice decrease orexin A release. In obese mice however, these receptors promote orexin A release.

According to researcher Ken Mackie, "Before, activating this receptor inhibited the secretion of orexin; now it promotes it. This identifies potential targets where an intervention could influence obesity." The researchers believe that the network of systems that help regulate food intake is reset in obese individuals in order to maintain the excess weight. They suggest that even when these individuals lose weight, the brain signals the body to consume more food in an effort to return to the heavier weight.

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• Key Shift in Brain That Creates Drive to Overeat Identified (Science Daily)

E. coli Bacteria Credit: Rocky Mountain Laboratories, NIAID, NIH

In response to the growing number of bacteria that are becoming resistant to existing antibiotics, researchers are developing synthetic particles that stop drug-resistant bacteria. Similar to the way antibodies seek and bind to specific germs, these particles identify and specifically target bacteria by shape. This shape selective method of targeting bacteria destroys the bacteria regardless of their antibiotic-resistant status.

The synthetic particles have been named colloid antibody particles. The researchers state that the synthetic colloid antibodies are small shells stuffed with a substance that is toxic to bacteria. In tests, the colloid antibodies successfully attached to and neutralized specific bacteria without harming other cells. The researchers project that colloid antibodies which selectively target bacteria by shape will be a formidable weapon against antibiotic resistance.

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• Fighting Bacteria With New Genre of Antibodies (Science Daily)

This image shows cancerous B cells that have been treated with rituximab. The protein CD20 (shown in green) has been drawn to the side of the cells. Image Credit: MCCIR

Researchers have discovered why the cancer drug rituximab is so successful at killing certain cancer cells. The drug effectively kills cancerous B cell lymphocytes by sticking to one side of a B cell and forming a cap. The drug reorganizes cell proteins toward that same side of the cell. This configuration allows other white blood cells, known as natural killer cells, to effectively recognize and destroy the cancerous B cells.

According to researcher Daniel Davis, "These results were really unexpected. It was only possible for us to unravel the mystery of why this drug was so effective, through the use of video microscopy. By watching what happened within the cells we could clearly identify just why rituximab is such an effective drug - because it tended to reorganize the cancerous cell and make it especially prone to being killed." The researchers state that these findings can be very useful in designing future antibody treatments for cancer.

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• Cancer Cells' Achilles' Heel Revealed (Science Daily)

Neurons Image: Dream Designs / FreeDigitalPhotos.net

Researchers from Case Western Reserve School of Medicine have developed a new technique for converting skin cells to a type of brain cell called an oligodendrocyte. Oligodendrocytes are central nervous system cells that wrap around some nerve cell axons to form an insulating coat known as a myelin sheath. They indirectly assist in the conduction of impulses as myelinated neurons can conduct impulses quicker than non-myelinated ones.

According to researcher Paul Tesar, "We are taking a readily accessible and abundant cell and completely switching its identity to become a highly valuable cell for therapy." In diseases such as multiple sclerosis and cerebral palsy, myelinating cells are destroyed and lost. The researchers state that a cure for these types of diseases requires the transplantation of replacement oligodendrocytes that can regenerate myelin sheaths around nerves. The researchers were able to generate billions of oligodendrocyte precursor cells that were successful in regenerating myelin sheaths in animal studies. They are hopeful that this technique can be used to treat human myelin diseases.

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• Ordinary Skin Cells Morphed Into Functional Brain Cells (Science Daily)

In this immunofluorescence microscope image of cancer gene Myc expressing cells, active death protein Bak appears as green spots localizing on the surface of the mitochondria. The blue staining marks the cell nuclei. Image Credit: Juha Klefstrom Research Group / University of Helsinki

The high energy molecule ATP is an important energy source for all cells, including cancer cells. Researchers have discovered that programmed cell death or apoptosis, occurs in cancer cells that experience drops in ATP levels. Normally, apoptosis is turned off in cancer cells because the tumor suppressor protein p53 is disabled. The researchers discovered that when ATP levels decline, cellular energy sensors modify p53 allowing it to move into cell mitochondria. Once inside the mitochondria, a cell death protein called Bak is activated which can trigger apoptosis.

The study centered on the Myc cancer gene. This gene causes changes in cell metabolism that increase a cell's ability to grow excessively, but also causes a reduction in ATP concentration. According to lead researcher Juha Klefstrom, "The (Myc) cancer gene dependent vulnerability to apoptosis has promise to be the prime target for future targeted cancer therapies but first, we need to understand the cell pathways that are causing this vulnerability. The investigated connections between Myc, energy metabolism and apoptosis will help us to understand the biochemistry of cancer cell apoptosis." The researchers believe that cancer cells with activated Myc genes are vulnerable to apoptosis due to their inability to stop growing, even when their energy source (ATP) is low.

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• Cancer Cell Metabolism Kills (Science Daily)