Nanobody project with alpacas, diabetes and Alzheimer’s research with mice – three selected research projects
Whenever possible, we replace experiments involving animals with alternatives such as cell culture or computer simulations. However, cell culture experiments in a petri dish or simulations at a computer are insufficient to understand complex biological processes in an organism. In our research on neurodegenerative diseases such as Alzheimer’s or Parkinson’s experiments involving animals remain indispensable; here, the mouse is an important model organism for mammals and especially for humans. The mouse also helps us understand how we adapt to light-dark cycles. Long since, individual mouse genes can be specifically manipulated by mutations. This affects the production of the corresponding protein for which the gene contains the building plan. The protein can be enhanced in its activity, can be inhibited, or can be missing altogether.
In the following, we introduce four of our research projects which involve animals.
Alpacas as “development workers” in the production of antibodies
Antibodies effectively protect us from diseases. In research and in medical diagnostics they are an indispensable tool, as well. Here, antibodies are chosen so that they specifically bind for instance a cancer protein or a molecule of high interest for research.
“Common” antibodies identify their antigens (for example molecular structures of viruses or bacteria) with the help of two protein chains, the heavy and the light chain. However, alpacas and other camels also produce simpler antibodies, which can be reduced to so-called nanobodies by means of molecular biology techniques. When labeled with fluorescence or gold, such nanobodies can be applied to localize a protein of interest inside a cell with highest precision.
Presently, 19 alpaca mares participate in the production of nanobodies as “development workers” at the institute. In such a nanobody project stress for the animals is minimal. First, an alpaca is vaccinated with the desired antigen (a purified protein) – this is comparable to our autumnal influenza immunization. The animal hardly feels the tiny pinprick. The antigens are prepared in a way that they are harmless for the alpaca. Its immune system then produces antibodies to fight the foreign body. About a quarter of a year later, a small amount of blood is taken from the alpaca from which scientists can isolate the building plans for these antibodies. Both the inoculation and the quarterly blood donation only take a few minutes. After that, the mare has completed its task and can return to its herd on the meadow. The stress is indeed so small that one animal can participate in a number of nanobody projects in the course of its life, while enjoying good life quality and high life expectancy. For us, all of these are important aspects of animal protection.
The main work then takes place in the lab using enzymes and bacteria. The blood sample initially contains the building plans for millions of different antibody variants. From all those, the ones identifying the desired molecule are picked. In the next step, E. coli bacteria produce the desired nanobodies in any required amount. With the building plans for the nanobodies known, the production can be repeated anytime and without the alpaca’s help. Another huge advantage: Many different nanobodies can be obtained from just one blood sample.
Our 19 alpaca mares are kept in a spacious enclosure that was designed according to the species’ needs with meadow and gravel areas, stables, and a sandy playground. The tame and trusting animals may be visited anytime at their freely accessible enclosure next to our Child Care Facility.
Diabetes: The control genes Pax4 and Arx
Diabetes is one of the most common metabolic diseases in western industrial nations. It is caused by insulin-producing cells dying in our pancreas. Researchers from our institute identified and analyzed two genes called Pax4 and Arx which are decisive for the embryonic development of the pancreas. The two genes were separately switched off in mouse strains so that the mice could not produce the respective protein anymore. When the Pax4 protein was missing, the mouse did not develop insulin-producing cells. Without the Arx protein the rodents did not grow glucagon-producing cells. Thus, both genes are fundamentally involved in the regulation of blood sugar levels. Today, their functions in embryonic development and in the adult organism are partly known. With the help of these results effective therapies for the treatment of diabetes may be developed in future.
Alzheimer’s & Co: Approaches for new treatment options
A frequent cause for neurodegenerative diseases are protein precipitates which damage nerve cells. In Parkinson’s, conspicuous precipitates of aggregated synuclein proteins in the brain can be seen under the microscope. The preliminary stages of these synuclein aggregates, so-called oligomers, are toxic for nerve cells. They lead to muscle tremor, movement disorders, and muscle rigidity in humans. Also in Creutzfeldt-Jakob disease harmful aggregates caused by so-called prion proteins are detectable.
Researchers at the institute succeeded together with colleagues at the LMU Munich in developing a promising drug candidate, anle138b. In studies with mice that show symptoms of Parkinson’s, anle138b prevented the formation of toxic oligomers. The compound delayed the destruction of nerve cells and extended the disease-free period. Mice treated with anle138b lived significantly longer and could much better control their movements compared to untreated animals.
Presently, the compound is further developed by MODAG AG to hopefully provide an effective drug for human patients in future.
Shift work and jet lag: preventing diseases
Shift working as well as traveling across time zones can disrupt the “inner clocks” in our cells. This does not only affect our sleep-wake cycle but can also lead to diseases like diabetes, arteriosclerosis, and cancer.
The cellular clocks in all tissues and organs of our body are controlled by the nucleus suprachiasmaticus (SCN), the central clock in our brain. The SCN synchronizes all the clocks in our organs with each other and with the light-dark cycle of our environment. However, it has not yet been fully elucidated how exactly this synchronization works.
In order to study the molecular and biochemical processes underlying the inner clocks, researchers at the MPI-BPC use – not least for animal welfare protection – cell culture experiments. Nonetheless, the physiological processes regulating the inner clocks effect many different organs and, therefore, can only be studied in living animals. To investigate those processes, researchers at our institute use the mouse as a model system, since its inner clocks are regulated in a very similar manner to ours.
By means of mice physiologists at the MPI-BPC examine, for example, how the inner clocks are controlled and what role the SCN plays in this context. To answer these questions, they genetically switched off the SCN in the brains of mice. Surprisingly, the rhythm of the clocks in the organs of these mice was not impaired. The animals even adapted more quickly to a shifted light-dark cycle. However, if mice without a functional SCN were kept in constant darkness for a week, the clocks in their organs desynchronized after a few days. These results suggest that there is another SCN-independent light-induced pathway synchronizing the inner clocks with the light-dark cycle of the environment. In the future, this novel signaling pathway could, in the future, lead to therapies preventing diseases among shift workers and frequent travelers.
Some years ago, similar experiments led to a potential approach to treat the negative effects of jet lag with the drug metyrapone. It is presently being tested in clinical trials to adapt it for human patients.