Reprogramming cells

In a study featured on the cover of the May issue of The FASEB Journal, researchers describe how they are able to reprogram human adult skin cells into other cell types in order to decipher the elusive mechanisms underlying reprogramming.

To demonstrate their point, they transformed human skin cells into mouse muscle cells and vice versa. Their methods included fusing the different cell types, so that their nuclei could chemically communication with each other. This research shows that by understanding the regulation of cell specialization it may be possible to convert one cell type into another, eventually bypassing the use of stem cells to achieve similar goals.

"Regenerative medicine provides hope of novel and powerful treatments for many diseases, but depends on the availability of cells with specific characteristics to replace those that are lost or dysfunctional," said Helen M. Blau, Ph.D., the senior scientist involved in the study, Associate Editor of The FASEB Journal, Member of the Stem Cell Institute, and Director of the Baxter Laboratory in Genetic Pharmacology at Stanford. "We show here that mature cells can be directly reprogrammed to generate those necessary cells, providing another way besides embryonic stem cells or induced pluripotent stem cells of overcoming this important bottleneck to restoring tissue function."

This is a useful bit of new information that might make our next discussion of cell differentiation . . . or the next stem cell use debate . . . a bit more interesting. Not that our discussions and debates are anything but interesting!

For the rest of the story, see the full press release:

Stanford scientists turn adult skin cells into muscle and vice versa
Contact: Cody Mooneyhan
cmooneyhan@faseb.org
301-634-7104
Federation of American Societies for Experimental Biology
Public release date: 30 Apr 2009

For the original research article, see:

Nuclear reprogramming in heterokaryons is rapid, extensive, and bidirectional
Adam Palermo, et al.
FASEB J. 2009 23: 1431-1440; published online as doi:10.1096/fj.08-122903

[Some contents of the above material are adapted from the press release.]

Meanwhile, on a similar investigative front, researchers recently showed that cells can be reprogrammed in a way that induces them to become pluripotent stem cells by treating them with a combination of proteins. The resulting induced pluripotent stem (iPS) cells can produce a variety of different cell types in the body (but not embryonic tissue).

This work gives even more weight to the concept that adult cells can perhaps be reprogrammed at will, for therapeutic purposes, using chemical signals rather than direct genetic manipulation.

Check out these resources:

Purely protein pluripotency
Elie Dolgin
The Scientist 23 April 2009
[Summary article of the original research; has a great image of iPS cells]

Metastable Pluripotent States in NOD-Mouse-Derived ESCs

Jacob Hanna, et al.
Cell Stem Cell 7 May 2009
doi:10.1016/j.stem.2009.04.015
[Original research article outlining the method used to induce pluripotency in adult cells.]

Growing new organs (and tissues)

You already know that scientists can grow tissues in the lab and physicians can transplant them successfully into living bodies, right?

A recent article in Scientific American brings us up to date on the rapidly progressing area of tissue and organ "farming."

Besides keeping us A&P professors up to speed on the latest practical applications of "why we need to know this stuff," the article does a great job of illustrating some of the core physiological and anatomical principles that affect such applications. For example, the article talks about the various concepts related to stem cells and development, as well as how the microenvironment of tissues affects their growth and development.

Check it out . . .

How to Grow New Organs
Pioneers in building living tissue report important advances over the last decade
Ali Khademhosseini et al.
Scientific American May 2009
[Great review article also includes related links and a nice photo of tissue growing on a 3D scaffold.]

EASTER EGG ALERT: Click on the thumbnail above to get a FREE image (including a PowerPoint slide) of how tissue can be grown and studied in the lab from a related PLoS ONE article Matrix Development in Self-Assembly of Articular Cartilage. (You may have to go to the blog at http://theAPprofessor.blogspot.com to get to the thumbnail or link if you are reading the this in a feed or newsletter.) article

What is life?

A video I saw on the web recently reminded me of the meaning of life. OK, that sounds a LOT more profound than I mean it to.

What I mean is . . . one of the most interesting questions in science
that I deal with is the most fundamental question, and one that comes right
at the beginning of my A&P course. The question is, what does it
mean for a human to be alive? What constitutes a living human organism?

Unbelievably, most courses set aside the core of that question and deal solely with the superficial aspects:

• defining living processes such as regulation, respiration, digestion, reproduction, etc.
• outlining the levels of organization with a human body: chemicals, cells, tissues, organs, systems
• describing the homeostatic nature of healthy human function

OK, I know it's only an beginning undergraduate course. I know that this is science and not philosophy (although I'm not certain of the distinction, really). I know we don't have much time in the course. I know the students don't really care about that right now (and quite possibly, never).

What really got me thinking about how central this question is to understanding the human organism was the book What is Life? by Lynn Margulis. Lynn, you recall, was the agent behind the serial endosymbiosis theory (SET) . . . which got us all thinking about how we can imagine ourselves more as a cooperative symbiotic community of organelles and cells than a distinct and fully integrated unit.

If the mitochondria in my cells can be thought of as bacteria-like symbionts, then am I not a collection of organisms rather than one organism? Well, no. By definition, a useful definition, my mitochondria ARE me and not a separate species living in me.

But we now know that I cannot survive without the proper functioning of the flora living on my skin, in my gut . . . just about everywhere my body makes direct or indirect contact with the outside world. Are these creatures, which are by definition NOT me, really a part of the organism? I wonder if our definition might change someday soon.

What got me thinking about this recently was a web video from a recent TED Conference and features a talk by Bonnie Bassler in which she really hones in on our concept of human life and relates it to the ability of some bacteria to regulate each other in much the same way that our cells communicate with and regulate each other.

[If you don't see the video viewer in your newsletter or feed version of this article, please go to The A&P Professor blog site to view it. Want to learn how to embed YouTube videos in your blog, website, or PowerPoint? Check it out at The A&P Professor website.]

Considering our rapidly growing understanding of our body as a set of interrelated functioning units­--perhaps even including the creatures that live on and in us--the day is upon us that we really need an understanding of what a single human organism truly is in a biological sense.

We really need such an understanding at a beginning, undergraduate level so that we can use it as a framework for building the kind of solid understanding that will inform our later studies . . . and our professional work as scientists and healers.

A skull a day . . .

There's a crazy, wonderful blog called SKULL-A-DAY that you should visit.

The project started out when this guy named Noah Scalin made a paper skull and posted it, then kept on making skulls in various media and in different forms every day for a year.

Then folks just kept adding to it and, well, now it's a pretty big project. There's even a book version now! The book is called SKULLS of course.

As most A&P professors are skull fans, or ought to be, I thought you might like to see all those skulls.

And maybe this'd be an interesting way to start class each day? Put the "skull of the day" on the first PowerPoint slide you use each day (or print it out and hang it up). Then maybe . . . just maybe . . . a few more students that usual will get there before class to see and discuss the new skull for the day.

And maybe . . . just maybe . . . some of them will intrigued enough to make and contribute their own image of a skull to the project! In fact, there's a contest going on right now to choose the favorite from among the original 365.25 skulls.

For Facebook users, there's an application called Send-A-Skull that allows you to send skulls to your friends. For any of you who are my Facebook friends, you probably already got one of these!

Hey, you never know what will be the thing to get an individual student more engaged in A&P!

Masters of Sex

I just downloaded the new book Masters of Sex to my Kindle.

Before I had a chance to get very far with it, I happened to tune into an interview with author Thomas Maier on our local public radio station. Now I'm even more anxious to explore this book further.

Maier does a great job of explaining and underscoring the pivotal role of William Masters and Virginia Johnson in discovering some of the basic principles of sexual anatomy and physiology.

Known to most as Masters and Johnson, in the book we come to know them as Bill and Ginny.

Most importantly, however, we more greatly appreciate their roles in pioneering the scientific study of sexual biology and developing therapies that (still) really help people. As we learn in the book, their accomplishments really were remarkable . . . and, alas, really are underappreciated.

I had the good fortune of knowing Bill Masters near the end of his life. He had just retired from the Masters and Johnson Institute when I asked him to be the keynote speaker at the 1995 Human Anatomy and Physiology Society (HAPS) Conference in St. Louis. He graciously agreed to something he had not done for years . . . and (as it turns out) never would again: speak at a scientific conference.

Wouldn't you think someone of his stature would have been a frequent speaker at such conferences? I asked him about that. It turns out that he was so vigorously harassed at scientific meetings (both by scientists in the meetings and protesters outside the meetings) that he adopted the strategy of avoiding such venues. But our meeting was different . . . we wanted to sit at the feet of the "Master" and learn about his adventures. He knew we were teachers wanting to learn and not suspicious investigators wanting to debunk.

And he did not disappoint! After showing us a film from his research program . . . a film of the "vaginal sweat" lubrication forming on the vaginal wall during the female sexual response (oh my gosh) . . . he regaled us with fascinating stories and anecdotes from a lifetime of pioneering research in the most fascinating area of human biology.

Bill and I spent many hours on the phone before and after that conference . . . he loved telling stories. His soft-spoken, self-effacing style of telling the stories seemed at odds with the honestly ground-breaking work he was describing.

All of my textbooks feature boxed essays that underscore the pioneering roles of Masters and Johnson. If you want to see why they deserve this place of honor, you'll want to read Masters of Sex.

Masters of Sex
Thomas Maier
Basic Books April 13, 2009 432 p.

Thomas Maier interview
St. Louis on the Air
KWMU/St. Louis 7 May 2009

Read about another great sex book at The A&P Professor website.

Memory T cells reside in bone marrow

When memory T cells form, where do they "hang out" until needed at a later time?  Scientists have debated this for some time.

Recent evidence recently published in the journal Immunity suggests an answer . . .

memory T cells prefer to reside in the bone marrow.

Until now, most immunologists believed that these cells circulate in the bloodstream.  So this is somewhat of a game-changer.  To me, this makes a lot more sense.  It seems that tucking memory cells away in the bone marrow conserves them more efficiently than free circulation would.

Here is a great article summarizing the discovery and its importance:

Home of immune memory found
Edyta Zielinska
The Scientist (NewsBlog) 7th May 2009

Here's a link to the original research article:

Professional Memory CD4+ T Lymphocytes Preferentially Reside and Rest in the Bone Marrow
Koji Tokoyoda, et al.
Immunity  07 May 2009

Click here for a FREE image showing red bone marrow in a fresh dissection of the humeral head . . . you can use it in a PowerPoint slide or in your syllabus or class notes.

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Fingerprint functions

The usual explanation for the presence of fingerprints, handprints, and footprints is to enhance friction and thus improve our ability to walk upright and to make and use tools.

However, recent evidence shows that these friction ridges (epidermal ridges) may also enhance our ability to sense fine textures on surfaces.

Researchers have found that artificial ridges similar to human epidermal ridges used with an artificial sensor were able to filter vibrations produced as the ridged surface brushes over a textured surface. This "filter" permits only vibrations around 250 Hz to reach the sensor--the same vibrational frequency detected by lamellar corpuscles (Pacini corpuscles) in the skin.

So the thinking is that skin ridges enhance the function of lamellar corpuscles and thus enhance our ability to sense fine textures.

Want to know more?

Fingerprints filter the vibrations fingers feel: ridges may help make touch sensation efficient
Laura Sanders
Science News February 28th, 2009; Vol.175 #5 (p. 10)
[Summary article discusses the implications of the recent research.]

The Role of Fingerprints in the Coding of Tactile Information Probed with a Biomimetic Sensor.
J. Scheibert, S. Leurent, A. Prevost and G. Debrégeas
Science, 29 January 2009. doi: 10.1126/science.1166467
[The original research report]