Introduction: Definitive Regenerative Medicine

• Levin’s goal: “Definitive Regenerative Medicine” – controlling what groups of cells build to solve birth defects, injuries, cancer, aging, and degenerative disease. Not just late-life interventions, but continuous rebuilding of structures.
• The “Anatomical Compiler”: A future system to specify a desired anatomical structure (e.g., a three-headed flatworm) and generate the stimuli to get cells to build it. Not a 3D printer, but a communication device.
• Focus: Understanding the cooperative action of cell collectives to build organs, both healthy and diseased. Moving beyond focusing solely on the genome, acknowledging cells possess inherent problem-solving abilities, similar to how individual cells such as *lacrymaria* have inherent survival capabilities without complex nervous systems, hinting at a pre-existing form of ‘cellular-scale decision-making’.

The Problem of Morphogenesis

• Where does body anatomy come from? Not directly from DNA, which specifies proteins (micro-level hardware). The question is how the collective activity of cells with this hardware builds the correct, species-specific “target morphology.”
• Fundamental knowledge gaps: Even with sequenced genomes (e.g., Axolotl, frog), we can’t predict anatomical outcomes of cell mixtures (e.g., “froglottl” legs). This is a collective intelligence question, not a hardware question.
• Need to go beyond molecular medicine: Current molecular medicine is like computer science in the 1940s/50s – focused on hardware (genes, proteins). We need a higher-level interface (like software) to reprogram cell behavior.
• Multi-scale competency architecture: Life has problem-solving at multiple levels (molecules, cells, tissues, organs, organisms). Each level has competencies in its own space (physiological, transcriptional, anatomical, behavioral). Examples of biological adaptability include *tadpoles developing eyes on their tails* connected via an optic nerve, enabling them to respond to visual cues, even without a direct brain connection.

Planaria: A Key Model System

• Planaria: Flatworms with remarkable properties: Regeneration (any body part), cancer resistance, and immortality (no aging). They constantly renew their tissues. The *regeneration record* includes successful regrowth after being cut into 275 pieces.
• “Messy” genome: Planaria have a highly mutated genome (accumulates somatic mutations) yet maintain perfect anatomical control. This challenges the idea that the genome is the primary determinant of form.
• Memory: Planaria can be trained, and this memory is retained even after head regeneration. This implies memory distribution outside the brain and imprinting on new tissue. This has implications for human brain regenerative therapies, which introduce new cells replacing decades-old memory/personality patterns.

Bioelectricity: The Software of Life

• Analogy to the nervous system: Neurons use electrical signals (via ion channels and gap junctions) for decision-making and moving the body through 3D space. This is “software” running on cellular “hardware.”
• Bioelectric signaling is ancient: It existed long before nerves and muscles. It’s used by *all* cells (not just neurons) to control body configuration through *anatomical morphospace*.
• Tools to read and write bioelectric patterns: Voltage-sensitive dyes visualize electrical conversations between cells. Techniques to manipulate ion channels and gap junctions allow us to rewrite these patterns.

Bioelectric Control of Morphogenesis

• Instructive bioelectric patterns: Changing the bioelectric pattern (e.g., inducing an “eye” pattern) can instruct cells to build specific organs (even in abnormal locations, like eyes on the tail). Demonstrating the adaptability of these biological systems when provided the correct stimuli.
• Modularity: The bioelectric code specifies *organs*, not individual cells. The cells themselves handle the complexity of building the organ (subroutine call analogy). Illustrates how tissues exhibit an inherent capacity to self-organize when triggered with the right set of commands.
• Recruitment: Cells with altered bioelectric states can recruit neighboring cells to participate in building the structure. Revealing a cooperative intelligence akin to the social behaviors found in insect colonies, such as those of ants and termites.
• Applications: Creating extra forebrains, legs, hearts, inner ears, fins (even in tadpoles, which don’t normally have them). Expanding regenerative capabilities in ways that exceed natural limitations.
• Limb Regeneration and Company Founding: Bioelectrical signals change rapidly after amputation. Frog Leg Regeneration is stimulated with a bioelectrical intervention, and it took only 24 hours of it. Levin Co-founded, with Dave Kaplan, a Company (Morpheuticals) which attempts Limb Regneration on mammals, mice currently.

Planarian Pattern Memories

• Rewriting body plan: A bioelectric circuit in planaria stores information about how many heads to have. This pattern can be rewritten (e.g., to create two-headed worms), and this change is *stable* (like memory). Single flatworm: A single flatworm may carry more than one instruction on its structure.
• Not a map of the current state: The bioelectric pattern is a “counterfactual memory” – it represents what the animal *will* build if injured, even if it looks normal now.
• Head shape: Bioelectric signals also control head shape. Blocking electrical communication can cause planaria to regenerate heads of different species (exploring “morphospace”).
• Latent ability: Exploring non-standard forms are within cell capacity.

Applications and Future Directions

• Computational Platform: Create full-stack bioelectric stimulations of what will happen with genetic/cellular info, so it may tell which ion channels will need open/close.
• Repairing brain damage: A computational model predicts which ion channels to manipulate to restore a normal bioelectric pattern in damaged frog brains (even with severe genetic defects). Using the bioelectrical signal restoration and the administration of approved anti-epileptics to stimulate neural repair and to recover not only brain structure, but cognitive function.
• Bioelectricity in Human Channelopathies.
• Cancer as a failure of collective control: Cancer cells disconnect from the bioelectric network and revert to a unicellular lifestyle. Forcing cells to remain electrically connected can suppress tumor formation even with oncogenes present.
• Physiological software layer: A tractable target for biomedicine, between genotype and anatomy. Cracking the bioelectric code (like neural decoding) will reveal how cell networks make decisions.
• AI tools: For designing specific strategies for regenerative medicine.
• Bioelectrical signaling: A “cognitive glue” binding cells towards a larger purpose (maintaining the organism).
• Bottom-up (conventional/hardware) and top-down (software) treatment strategies.
• Words and drugs having the same mechanism of action, quoting Fabrizio Benedetti: Bioelectricity provides communication.

Q&A Highlights

• Ion channel distribution: Complex patterns can arise even with uniform ion channel distribution (self-organization).
• Spatial Specificity and Signals in Wounds
• Neural Cellular Automata (NCA) collaboration: Acknowledged collaboration on “distal.pub” paper.
• Yamanaka factors: Important, but don’t address large-scale morphogenetic problems. Undifferentiated cells alone are not enough.
• Genetics vs. Physiology: Both are important (hardware and software). Physiology can override genetics in some cases.
• Aging solutions: Will likely fall out of solving morphogenetic control in general (along with regeneration, cancer reprogramming).
• Interface: genetics and quantum biology: Unknown currently; Classical is good so far.
• Money/Resource Limitation: Is where progress is stuck, not Fundamental Problems.
• Mapping bioelectric signal and gene expression, and to body/organ changes.
• Optogenetics use: Used in research, but clinical applications may be limited due to the need for gene therapy.
• Drug development for ion channels: Lots of activity, but the main bottleneck is a lack of physiomic data (bioelectrical state data in health and disease).
• Earth’s magnetic field: Not a major factor in the types of strong electrical exchanges studied.

引言：终极再生医学

• 莱文的目标：“终极再生医学”——控制细胞群构建什么，以解决出生缺陷、损伤、癌症、衰老和退行性疾病。不仅仅是晚年干预，而是结构的持续重建。
• “解剖编译器”：一个未来的系统，用于指定所需的解剖结构（例如，三头涡虫）并生成刺激，让细胞构建它。不是3D打印机，而是一种通信设备。
• 重点：理解细胞群体的合作行为来构建器官，无论是健康的还是患病的。超越仅关注基因组，承认细胞拥有内在的解决问题能力，类似于单个细胞（如 *lacrymaria*）在没有复杂神经系统的情况下具有固有的生存能力，暗示了一种预先存在的“细胞尺度决策”形式。

形态发生问题

• 身体解剖结构从何而来？并非直接来自DNA，DNA指定蛋白质（微观层面的硬件）。问题是具有这种硬件的细胞的集体活动如何构建正确的、物种特异性的“目标形态”。
• 基础知识差距：即使有了测序基因组（例如，蝾螈、青蛙），我们也无法预测细胞混合物的解剖学结果（例如，“青蛙蝾螈”腿）。这是一个集体智能问题，而不是硬件问题。
• 需要超越分子医学：当前的分子医学就像20世纪40/50年代的计算机科学——专注于硬件（基因、蛋白质）。我们需要一个更高级别的接口（如软件）来重新编程细胞行为。
• 多尺度能力架构：生命在多个层次上都有解决问题的能力（分子、细胞、组织、器官、生物体）。每个层次在各自的空间（生理、转录、解剖、行为）中都有能力。生物适应性的例子包括*蝌蚪在尾巴上发育出眼睛*，并通过视神经连接，使它们能够对视觉线索做出反应，即使没有直接的大脑连接。

涡虫：一个关键模型系统

• 涡虫：具有非凡特性的扁虫：再生（任何身体部位）、抗癌和不朽（不衰老）。它们不断更新它们的组织。*再生记录*包括被切割成275块后成功再生。
• “混乱”的基因组：涡虫具有高度突变的基因组（积累体细胞突变），但仍保持完美的解剖控制。这挑战了基因组是形态主要决定因素的观点。
• 记忆：涡虫可以被训练，即使在头部再生后，这种记忆也会保留。这意味着记忆分布在大脑之外，并印在新组织上。这对人脑再生疗法具有启示意义，这些疗法引入新细胞取代数十年前的记忆/人格模式。

生物电：生命的软件

• 与神经系统的类比：神经元使用电信号（通过离子通道和间隙连接）进行决策和在三维空间中移动身体。这是运行在细胞“硬件”上的“软件”。
• 生物电信号是古老的：它在神经和肌肉出现之前就已存在。*所有*细胞（不仅仅是神经元）都使用它来控制身体在*解剖形态空间*中的配置。
• 读取和写入生物电模式的工具：电压敏感染料可视化细胞之间的电对话。操纵离子通道和间隙连接的技术使我们能够重写这些模式。

生物电对形态发生的控制

• 指导性生物电模式：改变生物电模式（例如，诱导“眼睛”模式）可以指示细胞构建特定器官（即使在异常位置，如尾巴上的眼睛）。证明这些生物系统在提供正确刺激时的适应性。
• 模块化：生物电代码指定*器官*，而不是单个细胞。细胞本身处理构建器官的复杂性（子程序调用类比）。说明组织在用正确的命令集触发时如何表现出固有的自组织能力。
• 招募：具有改变的生物电状态的细胞可以招募邻近细胞参与构建结构。揭示了一种类似于昆虫群落（如蚂蚁和白蚁）中发现的社会行为的合作智能。
• 应用：创造额外的前脑、腿、心脏、内耳、鳍（甚至在通常没有它们的蝌蚪中）。以超越自然限制的方式扩展再生能力。
• 肢体再生和公司成立：截肢后生物电信号迅速变化。青蛙腿部再生是通过生物电干预刺激的，只需要24小时。莱文与戴夫·卡普兰共同创立了一家公司（Morpheuticals），该公司目前正在尝试对哺乳动物（小鼠）进行肢体再生。

涡虫模式记忆

• 重写身体计划：涡虫中的生物电回路存储有关有多少个头部的信息。这个模式可以被重写（例如，创建双头蠕虫），并且这种变化是*稳定*的（像记忆一样）。单一扁虫：单一扁虫的结构可能携带多个指令。
• 不是当前状态的映射：生物电模式是一种“反事实记忆”——它表示如果受伤，动物*将*构建什么，即使它现在看起来很正常。
• 头部形状：生物电信号也控制头部形状。阻断电通信会导致涡虫再生不同物种的头部（探索“形态空间”）。
• 潜在能力：探索非标准形态在细胞能力范围内。

应用和未来方向

• 计算平台: 创建对遗传/细胞信息会发生什么的完整生物电模拟, 因此它可以指示哪些离子通道需要打开/关闭。
• 修复脑损伤：一个计算模型预测要操纵哪些离子通道，以恢复受损青蛙大脑（即使有严重的基因缺陷）中的正常生物电模式。利用生物电信号恢复和已批准的抗癫痫药给药来刺激神经修复，不仅恢复大脑结构，而且恢复认知功能。
• 人类通道病中的生物电.
• 癌症是集体控制的失败：癌细胞与生物电网络断开连接，并恢复到单细胞生活方式。即使存在致癌基因，迫使细胞保持电连接也可以抑制肿瘤形成。
• 生理软件层：生物医学的一个易于处理的目标，介于基因型和解剖结构之间。破解生物电代码（如神经解码）将揭示细胞网络如何做出决策。
• 人工智能工具：用于设计再生医学的特定策略。
• 生物电信号：一种“认知胶水”，将细胞结合起来，实现更大的目标（维持生物体）。
• 自下而上（传统/硬件）和自上而下（软件）的治疗策略。
• 具有相同作用机制的文字和药物，引用法布里齐奥·贝内代蒂的话：生物电提供通信。

问答要点

• 离子通道分布：即使离子通道均匀分布（自组织），也可能出现复杂的模式。
• 空间特异性和伤口信号
• 神经细胞自动机 (NCA) 合作：承认在“distal.pub”论文上的合作。
• 山中因子：重要，但不解决大规模形态发生问题。单独的未分化细胞是不够的。
• 遗传学与生理学：两者都很重要（硬件和软件）。在某些情况下，生理学可以覆盖遗传学。
• 衰老解决方案：可能会从解决一般形态发生控制中脱颖而出（连同再生、癌症重编程）。
• 界面：遗传学和量子生物学：目前未知；到目前为止，经典方法很好。
• 资金/资源限制：这是进展受阻的地方，而不是基本问题。
• 映射生物电信号和基因表达，以及身体/器官变化。
• 光遗传学应用：用于研究，但临床应用可能会受到基因治疗需求的限制。
• 离子通道药物开发：有很多活动，但主要瓶颈是缺乏生理组学数据（健康和疾病中的生物电状态数据）。
• 地球磁场：不是所研究的强电交换类型中的主要因素。